Overclocking

I've done a fair amount of testing with my X3 720 Black Edition. My results should be more typical since I'm using the stock heatsink and fan

As I mentioned in my last article people who like Intel's new i5 and i7 processors could argue that the increased wear caused by heat stress doesn't matter because they'll scrap their system in three years anyway. At least, I assume that is what they would say; I haven't heard from anyone who actually uses an i5 or i7 and wants to talk about heat testing with stock HSF. So, it is possible that they are doing better than I have heard. However, with mine I prefer that my system can pass a heavy thermal load test.

I'm currently running:
Phenom II X3 720 Black Edition - 3.4 Ghz; Northbridge - 2.6 Ghz, auto voltage
I cannot hit 3.5 Ghz stable nor can I reach 2.7 Ghz with the NB setting.

OCZ AMD Gold Edition, 7-7-7-19-31, 1333 Mhz, 1.545 volts
To run with these timings I need at least 1.53 volts to be stable.

The standard test program is Prime95. However, this program doesn't give any indication of what is going on with the temperatures so you have to run something else. I ran AMD Overdrive on mine so that I could monitor the temperatures while Prime95 was running. At the very least I would reccomend running the AOD stability test. It is a good test but it doesn't raise the temperature like Prime95. I also tried Intel Burn Test which raises the temperature even more than Prime95 (but not 20 C as the author claims). Mine idles at about 25 C, hits 51 C with Prime95, and reaches 55 C with Intel Burn Test. However, IBT is so buggy that even if your computer crashes it may simply be due to IBT and not due to instability in your system.

For those looking for something simpler I would suggest OCCT 3.1. The regular test on this application heats the same as Prime95 while the Linpack test has heating similar to IBT. However, it also displays core temperatures in real time just like AOD. I would still suggest using a boot CD with MemTest86 to verify the memory. Early on my system would eventually BSOD and reboot even at 3.2 Ghz. So I had wondered if maybe the X3 720 wasn't as good as I had hoped. But, it turned out that the processor was fine and one of my 4 DIMMs was bad. I only confirmed this by running MemTest86. It is also very good at verifying the stability when you change timing or NB speed. I suppose the only thing I haven't tried is using a larger CPU cooler however I wouldn't really expect to get more than maybe 100 Mhz out this. I'm not sure a larger Cooler is really worth it for just 100 Mhz. I'm currently considering getting the new C3 stepping of Phenom II X4 965. With the heat from an extra core a larger HSF might be more worthwhile.

I also tried increasing the Integrated Graphics Processor speed but realistically I don't think you can get much more than 10% this way before your chip gets hot. You might even get 20%. However, I've tried running the free evaluation copy of PassMark's Performance Test and you can really see the graphics bog down. The early tests hit 140 FPS then as the tests get more difficult they go down to 60 FPS, 20 FPS, and 10 FPS. No amount of tweaking of the IGP is going to improve 20 FPS enough to be acceptable, much less 10 FPS. This requires a beefier GPU. So, I'm looking at HD 5770 cards right now. These are pretty close to the older HD 4890 cards so they should be able to handle most graphic loads.

About Intel's i7

So why is it that I seem to be so down on Intel when others think Intel and especially i5/i7 is the greatest thing since sliced bread? Well, I don't have an i5/i7 to test but there are people who do a reasonably good job of testing and don't have a glassy eyed love affair with Intel (like Anand Lal Shimpi). The truth is that Intel's C2D was an excellent processor. However, the initial batch of Kentsfield quads ran hot. In fact, they ran so hot that you could not clock even to 3.0 Ghz without exceeding the rated temperature when using the stock HSF. Ouch. However, the G0 stepping did fix this. And remember that this was at a time when AMD was struggling to hit 2.3 Ghz stock with its own quad core. Then in early 2008 the 45nm Penryns came out and this cut the temperatures even further. The FSB was a serious bottleneck with these quads but again AMD was only creeping up to 2.4 Ghz so it didn't seem to matter. So, Intel enthusiasts had every reason to feel a bit smug. However, by the end of Summer of 2008, AMD was at 2.6 Ghz and using the tweaked 750 southbridge the overclocks were no longer embarrassing. Instead, Intel's severe FSB bottleneck began to be an embarrassment. But, with i7 just around the corner, Intel enthusiasts were able to grin and bear it.

Unfortunately, for i7, it has been a two edged sword. Now that the memory controller is on the die instead of in a separate chip i7 fixes the FSB bottleneck, but i7 also has to handle the entire heat load just as AMD's quad Phenom had to all along. And, just whe i7 was picking up extra heat, AMD had the nerve to release a 45nm Phenom II that actually worked and reduced power draw (just as Penryn did for Intel). Today, heat is once again a serious problem for Intel. But, don't take my word for it. Here at
Benchmark Reviews, Cooling i7 you can see that even undervolted to 1.16 volts, an i7 920 running stock at 2.67 Ghz is 38.5 C over ambient using the stock HSF. So, if your house is 72 F you'll hit 60 C on your processor. Unfortunately, the reviewers were using liquid cooling on both the chipset and video card so most likely your case will be 5 C warmer. In Indiana in the Summer 85 F would not be unsual if you don't have air conditioning. Add 5 C for the case and you are just over the 70 C max that Intel specifies. This is without overclocking. In contrast, my X3 720 running 600 Mhz overclocked would run under 70 C with the same conditions.

Figure in overclocking and it gets far worse. Looking at Benchmark Reviews, i7 Cooling Overclocked we see that running i7 920 at 3.8 Ghz and 1.4 volts increases the temperature by 20 C. With the stock HSF, you would be 10 C over max even at 22 C ambient without a video card. Add in the video card and you are easily 15 C over max. Ouch. But its worse than that. According to the testing, even at 22 C ambient you could easily see 10 C over max even when using a ZeroTherm NV120. A Xigmatek HDT-1S283 or Tuniq Tower 120 will keep you within 70 C just as long as you don't try to push it higher than 3.8 Ghz. And, keep in mind these temperatures are after they laboriously polished the i7's integrated heat spreader to a mirror surface and used a Yate Loon D12SH-12 cooling fan on each product tested. The D12SH-12 cooling fan forces an impressive 88 CFM of air at a moderately noisy 40 dBA. Without these extras your results may be worse.

I know that at this point there will be Intel enthusiasts who will be in full blown denial. They will insist that going over 70 C is nothing and that you can of course go over 1.4 volts and they may even insist that it is impossible for a Phenom II to run cooler since they know that it draws more power. The sad truth though is this quote from the same article:

"The Phenom II processor series from AMD offer a very large 37.31 x 37.31mm (1392.04mm total area) integrated heat-spreader surface, which is the largest processor surface I can recall since the original Intel Pentium (I) days. Compared to Intel's Core 2 Duo and Quad processors which measure 28.5 x 28.5mm, the Phenom II offers over 71% more contact surface area. If you compare the latest Intel Core i7 processors which measure 32 x 35mm, then the Phenom II series offers 24% more contact surface area. For overclockers, this will mean a much larger area to cool, but also much more manageable temperatures."

And, there it is. If you are really committed to Intel and you don't mind spending time polishing the heat spreader and you don't mind the decibel roar of a high volume fan and you don't mind the extra cost of a bolt through kit and you make damn certain that your case is well ventilated then you can indeed get an i7 up to an impressive overclock. Or you could do something similar with a Phenom II with a fraction of the effort because of its 24% larger heat spreader. And, adding insult to injury, AMD just released the C3 Stepping of PII 965 which gives AMD another 100 Mhz bump in overclocking to 4.0 Ghz. Can you match this with an i5 750 or i7 860? Yes, you can but it sure won't be easy. To paraphrase Robert Heinlein, the Intel i7 is a harsh mistress.

Update on new system

Even with the stock HSF, AMD's Phenom II X3 720 is a nice overclocker.

Case - Cooler Master Storm Sniper
Power Supply - Corsair Professional series 850 watts


Motherboard - Asus M4A785TD-V EVO
BIOS 4.10

Processor - Phenom II X3 720 BE, stock HSF
Bus, 200 * 17 = 3.4 Ghz, auto voltage
NB, 200 * 12 = 2.4 Ghz, auto voltage

Memory - OCZ AMD Gold Edition, 4 DIMMs, Unganged
Total, 4 * 2 GB = 8 GB's
Clock, 667 Mhz, 1.45 volts
Timing, 7-7-7-19-30-2T

Memory tested with a two full cycles of MemTest86 4.0 from boot CD. Processor tested with Prime95 using one thread per core of In-Place, Large FFT (maximum heating) which hits just over 50 C. Also tested with two passes of Intel Burn Test, 10 cycles each. IBT is only useful to raise the temperature; you have to ignore the numeric results since IBT has errors in calculation.

I had one bad DIMM from OCZ that I RMA'd without too much trouble and got my replacement. The Case had a bad circuit board which prevented the pretty blue fan lights from coming on. They sent me a new top which I swapped out with the old one and the lights work fine now. I haven't had any other problems with hardware. With Windows Vista though there were a couple of things. When it first installed some of the menu items like Accessories were missing. Later it developed a Component Store error which could not be fixed. This prevented upgrading to service pack 2. In the end I had to reformat and reinstall Vista. This install seems to be working just fine and it successfully installed service pack 2. I will upgrade to Windows 7 as soon as Microsoft sends me my copy. Theoretically it was shipped today.

I am curious though about Intel Nehalem based systems. I've seen people who claimed with a straight face that 85 C was okay because the CPU wouldn't be damaged until the temperature hit 100C. I'm baffled where this notion comes from. It seems to be a naiive assumption that since thermal throttling occurs at 95 C that anything below that must be safe. Thermal throttling seems analogous to me to a rev limiter on an engine. Engines have a green band where the engine normally runs, a yellow band where damage will eventually occur and a red band where damage can occur at any time. Rev limiters are normally set to hold RPMs within the yellow band and prevent moving up into the red. However, I have seen limiters which even allowed moving slightly into the red. If you aren't familiar with the notion of green, yellow, and red bands for RPM range this is an excerpt from an engine manual:


ENGINE OPERATING RANGE
Idle 1300-1600 RPM
Continuous cruise 3200-4800 RPM Peak torque @ 3600/100% throttle
Max continuous 5000 RPM Peak in-flight HP/100% throttle
Max peak / Time 5600 RPM / 5 Minutes Ignition rev limiter set @ 5900
Never exceed 6000 RPM Engine mechanical limit.

Here we have a direct comparison to processor temperatures. Obviously Idle would be the no load temperature with minimum clock. Continuous would be up to Intel's maximum temperature which on i7 920 would be 70 C. This is the green band where the processor was designed to run. Next we have the yellow band which for this engine runs from 4800 - 5900 RPM where the rev limiter kicks in. This is directly analogous to the temperature band on i7 920 which runs from 70 - 95 C where thermal throttling occurs. The never exceed limit is 6000 RPM which again is directly comparable to Intel's 100 C limit.

Now, notice that the maximum peak is 5600 RPM even though the rev limiter doesn't kick in until 5900 RPM. Peak is not an RPM that you can run on a continuous basis; the maximum continuous is only 5000 RPM. Increased wear occurs if you run above 5000 RPM for any length of time. The same thing happens when running a CPU above rated temperatute. The big difference though is that the engine can be overhauled whereas the procesor will have to be scrapped. I've seen overclockers blandly assume that Intel temperatures were fine because "thermal throttling didn't occur". This is almost certainly incorrect. Occasional jumps into the band above 70 C shouldn't cause any noticeable effects just as they don't when briefly revving into the yellow band with a engine. However, continuously running above 70 C is not just asking for trouble; it is sending out an engraved invitation.

So, what exactly does this mean in real terms? First of all, both Intel and AMD expect CPU's to have a lifespan of 30,000 - 50,000 hours. Secondly, for every 10 C you go over 70 C you decrease life expectancy by half. So if you ran something like Prime95 continuously with it stressing your processor to 85 C, life expectancy would be 1.2 - 2.0 years. The problem is that it would be difficult to reach this temperature with something like Folding@Home and few other applications would run continuously. Routine tasks like web browing and word processing will hardly stress the CPU above idle temperatures. In other words, if your temps stayed under 70 C then the couple of hours a day you spent playing Call of Duty with your temps hitting 85 C would be neglible on CPU life.

If you ran your CPU at 75 C continuously doing something like encoding and then hit 90 C for three hours a day playing Crysis then your CPU life would be 2.1 - 3.5 years. If you planned to upgrade in three years it might be worth the risk. However, keep in mind that your video card and memory (and sometimes the power supply) get their cooling air from inside the case. If the case temps are high because of heat from the CPU then it would be a good idea to either upgrade the case fans or to avoid overclocking memory or GPU. And since the power supply typically has twice the life expectancy of the CPU I would avoid using a case where the PS has to draw from the interior. For example, in my case, the PS draws cooling air through a screen on the bottom so it doesn't get warm air from inside the case. Over at Toms Hardware you can see a perfect example of a poorly design system where they tried to stuff a hot i7 920 into a micro-ATX case with two GTX 295 graphic cards while using a PS that draw from inside the case:


The problem was that the cooler’s heatpipes would interfere with the DFI LANParty Jr. motherboard’s heat sinks, making it impossible to mount the CPU cooler in such a way that would force CPU-heated air towards the rear case fan, and therefore, out of the case.

We were left with no choice except to channel heated air upwards (toward the PSU) or downwards (toward the video cards). Given these choices, we would prefer to force it upwards toward the PSU so that it could be channeled through the power supply and out of the rear of the case.

Unfortunately, in this specific application, the PC Power and Cooling S75QB PSU does not pull air from below like a lot of ATX PSUs do–one fan pulls air in from the front of the PSU, and then another fan forces it out the rear. The bottom of the PSU is solid, and pushing CPU heated air upwards into a brick wall isn’t our idea of a good time.

We were left with no choice at all, really: we had to push the CPU-heated air downward, towards the graphics cards.


Contrary to what the fools at THG suggest, the last thing you want a good power supply to be doing while under heavy load is acting as an exhaust fan for the CPU. This irrational power-supply-as-cooling-fan notion began with Intel's desperate BTX case. Likewise, if your CPU runs hot then avoid using the the cheap video cards that exhaust inside the case. In another THG build they put four cheap, internally exhausting video cards inside the case. However, the NZXT Tempest case they used includes two front fans, one rear fan, and two top fans so it would be able to handle the case cooling with no problem. However, once again we see the completely bogus link with the power supply:

It's a little ironic that the reason a PC Power & Cooling PSU wasn't ideal for our previous microATX build is precisely what makes it so attractive this time around. In our last SBM, we experienced less-than-ideal airflow out of our CPU cooler because the power supply didn't pull air from below.

This is absurd. The cooling air will be drawn in the front and exhausted out the three fans in the top rear corner. Having the power supply sucking in air on the bottom of the case would actually reduce the cooling efficiency since you want it to exhaust out the top. The builder even recognizes this point in opposition to his previous statement about the power suppply:


The Xigmatek Dark Knight can dissipate a good amount of heat for the $37 price tag, which we’ll use to push the hot CPU and GPU heated air upwards and towards the NZXT Tempest case's upward-facing exhaust fans.



I'm not against overclocking. I specifically bought a BE processor to make overclocking easier and the system more stable. The highest clock I can reach and still boot Windows is 3.6225 Ghz (17.5 x 207 Mhz). I can boot, run SuperPi, open a paint program, paste, clip and save the image. I can open a browser, go to a website, and upload the resulting image. I can do this at 3.6225 Ghz and with the stock HSF. I don't consider this practical though. The highest clock I can hit and still pass Prime95 is 3.485 Ghz. Again, on the stock HSF. So, I run mine at 3.4 Ghz to have some margin of stability. Temperature has never been a problem. The max temperature for my processor is 73 C. With Prime95 I can hit about 51 C and with Intel Burn Test I can hit 55 C. Both are well below the maximum.

I guess reasons like these are what turned me off from the idea of running a Nehalem system. You never hear Intel enthusiasts talk about the stock HSF; they always use a premium cooler like a Zalman or Thermaltake. In fact, when Intel sent out socket 1156 i5's and i7's for review they included Thermalright MUX 120 coolers. This heatsink is 160mm's tall which means it would fit in my case as long as I don't have a fan on the side panel but would not fit in most cases. When the manufacturer has to include a premium cooler something is definitely amiss.

The bottom line is that the days of the cool running Penryn's are gone. However, we also know that Penryns ran cool because the memory controller was in a separate chip. Now that Intel has the memory controller on the CPU die the entire thermal bill must be paid from one socket instead of going Dutch with the Northbridge. I would guess that Intel enthusiasts want to pretend that they can get the benefits of the IMC while keeping the low thermals of Penryn. Since this doesn't work so well, they resort to downplaying the notion of going over the rated temperature, and they seem to avoid doing stress testing with programs like Prime95. That all seems very strange to me. You pretend you have a robust processor and then handle it with kid gloves. I think the denial started when reviewers found out that Turbo often wouldn't work in a standard case with a video card. Also strange is the notion of touting Turbo as a great feature but then having to turn it off to overclock. I like AMD's Cool and Quiet and it stays on and running all the time. This allows the processor to clock down to 800 Mhz at idle.

Now, I have encountered the same attitude about ignoring common sense limits on AMD hardware but you have to search a lot harder to find it. For example when I was installing the processor on the motherboard the stock HSF seemed pretty hefty to me. I had a hard time imagining using something much heavier. However, I was wrong; the actual AMD spec for socket AM2/AM3 indicates a weight limit of 500 grams which is quite a bit heavier than the stock unit. 500 grams should be plenty but these example heatsinks are compatible with AM2/AM3 and heavier:

Sunbeam CR-CCTF - 590 grams
XIGMATEK HDT-D1284 - 667 grams
ASUS Royal Knight - 790 grams
Xigmatek THOR'S HAMMER HDT-S126384 - 800 grams
COOLER MASTER V8 RR-UV8-XBU1-GP - 867 grams
ZALMAN CNPS10X Extreme - 920 grams

All sorts of nasty things can happen if you flex the motherboard too much. Just as we find Intel enthusiasts who rationalize running over temperature limits I'm sure the AMD enthusiasts who buy these heatsinks would have similar rationalizations for going over the socket weight limit. However, I'm not looking for denial, excuses, or rationalization. A decent processor should be capable of running in a standard case with the stock HSF and still passing Prime95. If you have to make excuses why your system can't do this then you don't have much of a system.

While I'm at it I might as well talk about the AMD 785 integrated graphics. Dawn of War is almost more than the graphics can handle; I have to run it on absolute minimum settings. Sins of a Solar Empire actually has the same graphic requirement so again turning things off is a good idea. DemiGod has higher graphic requirements and is jittery at 1280 x 1024 even with minimum settings so you'll be near the bottom in graphic resolution. All of these games are enhanced for multi-core but apparently not enough to offset slower graphics. In other words, I'm not sure that my X3 processor is noticeably faster than it would be with an X2 and I'm pretty sure that an X4 wouldn't make much difference. They are playable but more resolution would be nice. Presumably these would be unplayable with Intel X58 graphics or older ATI 690G. Of course, low end discreet cards are not that expensive unless you are trying for a budget system. I had been looking at AMD 4890 cards before the 5000 series was released. Now it looks like the 5770 Juniper cards have displaced the 4890's and have Direct X11 support as well. I had considered 5850 but the cost is higher than I want to go. I'll have to revisit the performance when I upgrade.

New System

I waited to get enough spare money and then waited because of rumors of the 3.4 Ghz Phenom II 965. So, I decided to stop waiting and put together an interim system.

I didn't really care for the wattage bump on Phenom II 965 to 140 watts. I figure that AMD will probably release a new one at 125 watts like they did with Phenom so I'll wait for that one before getting a quad core. I did briefly consider Intel but unfortunately the Penryn based quad cores are pretty much obsolete because of the FSB bottleneck. That only left i7 920 but I didn't feel like spending all the extra money for little additional CPU power. Also tipping the scale was that I decided to wait for AMD's 5000 series GPU's to see how good they are. But with an Intel motherboard I would be stuck with some truly second rate graphics. Maybe if i5 were out there would be a genuine option from Intel but right now, it doesn't exist. I picked up:

CPU: Phenom II X3 720 Black Edition (tri-core)

Motherboard: Asus M4785TD-V EVO

Memory: 4 x 2GB DDR3 OCZ Gold AMD edition (capable of DDR3-1600)

Power Supply: Corsair HX 850 W Professional Series (modular)

Harddrives: Western Digital 640 GB, 1 TB, and a Western Digital Elements USB 1.5 TB external

DVD drive: Lite On DVD reader

Monitor: Asus 21" LCD

OS: Vista Home Premium and OpenSuse Linux


I'm using the stock HSF so overclocking is limited primarily by cooling. That is fine since I'm not really interested in any severe overclocking. To test stability I run Prime95 with maximum heating. From every test I've done Prime95 always comes up as the toughest. I've found that running windows is not as stressful as running the stability tests in AMD OverDrive and the AOD tests are not as stressful as Prime95. This makes the common practice among overclockers of "being stable enough to get a SuperPi score" something of a joke. I wouldn't trust a system without running the toughest stressor to see exactly where I stand.

The M4A785TD motherboard has had a few BIOS updates. I installed the latest one. I wasn't really interested in trying to unlock the 4th core as some have done since I knew that this would be a weak core. However, others asked me about it so I did give it a try. I was unable to show a 4th core with any configuration using Asus' Unleashed mode. Also, even though the BIOS has an option for setting the NorthBridge multiplier independently of the HT clock it doesn't work. Maybe in the next BIOS update. So, in order to increase the NB speed I have to bump the base clock just as people would have to if they didn't have a Black Edition with unlocked multiplier. I'm running memory in Auto which defaults to ganged mode but I don't know that that makes any difference in stability. Perhaps it would at 1600 but with only three cores I don't really need more than DDR3-1200. With CPU and NorthBridge voltage on auto, memory set to 1.59 volts and 533 Mhz, I ended up with:

250 Mhz base x 13 = 3.25 Ghz is stable. However, the 2.5 Ghz NB is overkill. With all 4 DIMMs I get 667 Mhz with a latency of 7 and 1T command rate.

238 Mhz base x 14 = 3.332 Ghz is stable. The 2.38 Ghz NB is still higher than it needs to be. With all 4 DIMMs I get 634.7 Mhz with a latency of 7 and 1T command rate. If the multiplier were locked this would be the fastest configuration.

231 Mhz base x 14.5 = 3.35 Ghz is stable. The 2.31 Ghz NB is okay. With all 4 DIMMs I get 618 Mhz with a latency of 7 and 1T command rate.

225 Mhz base x 15 = 3.375 Ghz is stable. The 2.25 Ghz NB is about right. With all 4 DIMMs I get 600 Mhz with a latency of 7 and 1T command rate. This one or the following one seem to be about the best all around configurations.

219 Mhz base x 15.5 = 3.395 Ghz is stable. The 2.19 Ghz NB is not too bad. With all 4 DIMMs I get 584 Mhz with a latency of 7 and 1T command rate.

212 Mhz base x 16 = 3.392 Ghz is stable. The 2.12 Ghz NB is about the lowest I would want to go. With all 4 DIMMs I get 565 Mhz with a latency of 7 and 1T command rate.

206 Mhz base x 16.5 = 3.398 Ghz is stable. The 2.06 Ghz NB is a bit slow. With all 4 DIMMs I get 549 Mhz with a latency of 7 and 1T command rate. If I specify 667 Mhz in the BIOS the memory defaults to a latency of 9 and 2T command rate. I might be able to tweak the settings back to 7 and 1T, but with the slower NB it wouldn't be worthwhile.


Update:

i5 750, i7 860, and i7 870 were not out yet when I ordered my components. However, now that I've seen the reviews it is clear that these processors wouldn't have mattered anyway.

Remember back when AMD released the B3 stepping of Phenom in early 2008? AMD discovered something that they had overlooked. Their processor wasn't playing nicely with the 700 series southbridge. So, AMD released the new 750 southbridge; and, when these Phenoms were used with motherboards having the 750 southbridge, it made a difference. You could easily get 200 - 300 more Mhz on an overclock. With that painful lesson under their belts, AMD upgraded the phase lock loop in the 45nm Phenom II's so that they got the same benefit whether you used the new 750 or the old 700 southbridge.

However, Intel has apparently fallen into the same experience trap with the newest processors. These chips have PCI-e on the die itself. Great for reducing cost but not so great for overclocking. Intel ties the PCI-e clock to the BCLK much as AMD has tied the HyperTransport frequency to its base clock since K8. Even Anandtech admits that getting away from 133 Mhz multiples will cause PCI-e problems. In contrast I had no trouble running the base clock up from 200 Mhz to 250 Mhz; HyperTransport still worked fine. Secondly, as you increase the frequency on Intel's newest processors it destabilizes PCI-e because the drive transistors cannot keep up at stock voltage. The solution would normally be to overvolt but unfortunately this can't be done very well with Intel's stock HSF. In fact, Anandtech used the word "sucks" several times in describing overclocking with the stock HSF. Anandtech claims a top clock of 3.37 Ghz for the i7 870 with stock HSF. This would be the same as what I'm getting however given Anandtech's checkered history with testing I have to assume that they did not try running Prime95 on all four cores with maximum heating as I did. This sounds like it would easily knock their claim down to the same 3.2 Ghz stock that Chile Hardware was able to get.

This is a problem for Intel if you really want more performance. Anandtech also says that you need to disable Turbo if you want the maximum clock without crashing. However, they then say that you need to leave Turbo on to let the system clock down the cores individually to avoid wasting power. And, even though Intel quietly suggested that reviewers use the Thermalright MUX 120 premium cooler to solve Lynnfield's thermal woes, Xbit Labs saw temperatures of 93 C under load at 4.07 Ghz. No thanks. Maybe Intel will fix these hardware issues in the newer 32nm i5's and i7's but for now these chips have issues. Nor have I even mentioned the problems encountered in trying to get Turbo to work under Linux or the way Turbo is unlikely to work in a standard case with a nice video card installed.

To get the current speed on my system I only had to change the base frequency, the multiplier, and bump the DIMM voltage to 1.59. The CPU base and NB voltages and DIMM timing are all on auto. Even with the bump in speed however I'm still running both the CPU and memory under their maximum rated voltage. My processor idles at 900 Mhz at 25 C and runs up to 3.375 Ghz with about 48 C under Prime95 load. If Intel were able to do this then they would have something to brag about.

I don't know what some of the reviewers have been thinking but worse overclocking than Bloomfield with 33% less memory bandwidth hardly sounds like a revolution. PCI-e onboard to reduce cost while also sabotaging overclocking sounds more like a reluctant compromise than a feature. And less functionality with a higher price tag than Phenom II is just not my idea of a good deal. Intel has a few obstacles to overcome (or a sharp price cut) before the new i5's and i7's will be genuine competition for AMD's Phenom II's. However for anyone with money to burn, a premium cooler, and a calm disposition the new Lynnfields could provide endless hours of fun trying for a high SuperPi score. I would stay away from Prime95 though at least until Intel comes up with a solution to the PCI-e problem.