A First Look At AMD And Intel Stock Coolers

This is rundown of the stock coolers for the Intel i5 and AMD Phenom II processors that I have along with third party coolers.

Click to enlarge any of the following images.

On the left is the stock cooler for the Intel i5-750. On the right is the stock cooler for the AMD Phenom II X3 720. The Intel cooler weighs 250 grams while the AMD cooler weighs 280 grams.

The Intel cooler has a larger fan.

Both heatsinks are solid aluminum. You can see that that the AMD heatsink is taller.

On the left the AMD heatsink has the thermal paste removed down to bare metal. AMD has a solid aluminum heatsink while the Intel heatsink obviously has a copper core. Both processors are rated at 95 watts. The Intel processor probably draws a little more but the copper core and larger fan would take care of that.

The X3 720 cooler is on the left while on the right is the cooler for the AMD Phenom II X4 965. You can see that both fans are the same size. However, the X4 965 fan has deeper blades which probably help move air against higher back pressure caused by the closer spaceing on the cooling fins. The X4 965 cooler weighs 355 grams.

Here you can see that while the X3 720 heatsink is solid, the X4 965 heatsink uses two heatpipes on each side. This is necessary to cope with the greater 125 watt rating.

Update: I was not entirely happy with the stock HSF for PII 965. It is adequate at the stock speed of 3.4 Ghz and probably 3.6 Ghz. However, it does tend to blow hot air on both the motherboard chipset and the memory. And, with my particular case arrangement I have a large, 200mm fan right above the cooler that draws upward. However, because the fins run left and right this is no benefit.

Here you can see that the base of the X4 965 heatsink is all copper. On the right is a third party cooler. This is the Arctic Cooling Freezer 64 Pro. It weighs 530 grams. It has a copper base and three heatpipes on each side. The heatsink is obviously much larger. It also has the standard latching mechanism used on socket AM2/AM2+/AM3.

Update: The Freezer 64 seems much better. I was very concerned that the fan would not clear the DIMMs on the right side of the cpu socket. You can see this in the above picture. The problem with this is that it would have required me to turn the cooler around and then the fan would be blowing backwards. However, it does indeed clear the DIMMs.

Most people wouldn't have the very large fan right above the cooler; but you can see that even with the boxing effect of the video card, the air is directed properly toward the rear case fan. This is much better than the stock fan since it draws cooling air across the DIMMs and then blows cooling air across the chipset heatsinks behind the CPU socket. The air coming from this heatsink is much cooler than it was from the stock heatsink, presumably because of the increased airflow from the larger fan. There may also be some benefit from the vertical draw from the large fan since the fins are aligned vertically.

Here are the X3 720, X4 965, and third party Freezer 64 side by side. The Freezer 64 has a much larger 92mm fan.

On the right is the Arctic Cooling Freezer 7 Pro which can be used on both Intel and AMD sockets. It has the same size heatsink and same size fan as the Freezer 64.

A good thing to have handy for overclocking is a better case fan such as this Scythe unit.

Also good to have handy when swapping coolers is thermal compound cleaner and extra thermal compound such as these from Arctic Silver.

I'm current running my PII X4 965 at 3.8 Ghz with the NB at 2.6 Ghz. This seems pretty stable. I've been able to pass OCCT Linpack at about 60 C at 3.9 Ghz. I'm a bit disappointed that I couldn't get the NB up to 2.8 Ghz. I'm not sure how much of this is due to the BIOS. The version I'm using is the very first version that works with this processor.

My opinion so far is that if you have an X3 720 there is very little reason to replace the stock cooler, however I like the Freezer 64 much better than the stock cooler on the PII 965. The Freezer 64 matches the normal weight allowance of 500 grams and since it uses the same cam latch, it installs just like the stock unit. The extra airflow means that the exhaust air is much cooler and this is something I greatly prefer for the motherboard.

Laying The Ground Work For Proper Testing

I've seen reviews of AMD's Phenom II and Intel's Nehalem. These reviews have varied a lot in quality but none have really provided comprehensive results. It's time to find out.

I originally bought an AMD Phenom II X3 720 Black Edition. Mainly I did this to have something to try out while I was deciding what quad core to buy. The 955 BE looked pretty good. The 965 had a higher base clock but was also more expensive and was rated at 140 watts. On the Intel side, the i7-920 was still much more expensive than the PII 965. But, recently, this all changed. AMD released a new C3 stepping of PII 965 that is rated at 125 watts. Surprisingly, it was released at $200 instead of the $250 that most had been expecting. So, I ordered one. And, I ordered an Asus M4A79X motherboard which is similar to my MA4785 board but without graphics. I also purchased an ATI HD 4650 and couple of ATI HD 5770 graphic cards.

Then I noticed that the i5-750 was the same price, $200, and that I could get an Asus P55 motherboard without graphics that was almost identical to the 79X board and the same $120 price. I ordered those as well. This will give me two almost identical systems. Both systems will be native quad core with onboard memory controller and two memory channels. This should be an excellent head to head, dollar for dollar test. I'll use DDR3-1600 memory rated at CL 8. This makes the most sense because CL 7 memory is still less common, and faster memory rated at 1800 - 2100 Mhz tends to be twice the cost. I'm getting a couple of moderate sized third party coolers to test overclocking although I'm also interested in how much headroom there is with the stock HSF. Moderate sized is close to 500 gram weight, under 130mm's tall, and using 92mm fans. This compares with the heavy coolers which tend to be closer to 160mm's tall, weigh upwards of 700 grams, and use 120mm fans.

The hardware is perfect; this is the closest match of AMD and Intel hardware that I've seen in a number of years. I don't think we've had this close of a comparison since the K7/K8 single core days. The question now is how to test. I'm working on that. My game Dawn of War has a graphic check so see what level is playable. With my IGP 785 graphics the game is only playable with minimum settings. I can check this again with HD 4650, HD 5770 and HD 5770 Crossfire. To be honest, I don't expect to see much difference between the i5 and PII 965 systems. I'll also compare with my X3 720 to see if having another core makes any difference. PassMark has Peformance test which also includes both 2D and 3D graphic tests. I can say that my 785 graphics fail miserably on the last two tests. I'll give these a try but I wouldn't be surprised if they are low enough stress that even the 4650 card passes. I'm hoping that Dawn of War will be require a bit more although it too may top out before reaching the level of Crossfire.

For Integer testing I'm thinking about something based on GMP since this library shouldn't be tuned for either AMD or Intel. Use of the Intel Compiler is obviously out since this would contaminate the metrics. I have Visual Studio but this compiler is only middle of road in terms of what it produces. The next version is looking much better and it is just now available in Beta so we'll see. Better code would be nice but bugs in the Beta version could also contaminate the metrics. However, even the current version should be adequate with Integer code; it is the SSE code that is more of a concern. SSE2 is getting a bit dated. SSE3 is about the minimum level that would be nice to test. Better would be SSE4a versus some or all of Intel's SSE4. I don't have a requirement for full SSE4 testing since a fair bit of this will be replaced with Intel's next upgrade much as SSE became less important as wider SSE functions were added.

My operating system is 64 bit. I'm using 8 GB's memory and see no reason to waste time with 32 bits. Anything that I compile will be 64 bit. I do plan to test with both 2 DIMMs and 4 DIMMs to see if there is any difference. With my system I haven't seen any significant difference in timing or top speed. The two standard cases that I'll be using are both CoolerMaster cases with 200mm fans in front and top and a 120mm fan in the back. I do have a smaller case that only has a single 120mm fan in the back which I could test with. Personally, the notion of putting a $200 processor in a $60 case seems a little goofy but this could show what type of environment would be acceptable. Frankly I wouldn't be surprised if the 125 watt PII 965 were too much for that case.

I'm also glad that I got the X3 720 first since it is rated at 95 watts just like the i5-750. This should give me a pretty comparison of two 95 watt systems although since the i5 is a quad core I would expect it to be more powerful. I suppose if the i5 turned in thermals similar to my 720 while matching the performance of the 965 that would be quite a feather in Intel's cap since it would mean that i5's could be used in smaller cases with less cooling. Overall, it wouldn't be any great victory though since there is no price advantage. Of course, it has been suggested that Intel's power rating is bogus and is actually higher than they claim. Others have tested and insisted that Intel draws less power. Again, I don't really care about previous power draw tests since I have a 95 watt X3 and a 125 watt X4 to compare with. I suspect that since i5 is on the lower end of the Nehalem range it will actually fall in between these two but again I don't know without testing.

And, I have two graphics-free motherboards so I can test without the contaminating effect of integrated graphics. Given the huge gap between AMD and Intel integrated graphics there really is no way to directly compare them. The simplest solution is to discard the integrated graphics and use the same discreet graphic card. For lower level tests or small case tests I would use the HD 4650 which is a pretty solid, middle of the road card. I wouldn't expect a small case with one 120mm fan to be able to handle one 5770, much less two; nor would I expect it to handle an overclocked 125 watt processor. I know that I haven't had any thermal problems with my X3 720 but the case is well ventilated and it is only a 95 watt processor with integrated graphics. If i5 with 4650 does not pass a small case test then I can still project how well i5 would do with integrated graphics by comparing with 720 and the 785 motherboard. And, if the tests are borderline I picked up a heftier, 40 CFM, 120mm Scythe fan which would boost cooling in the small case. This should allow a pretty good inference for cooling with two regular 120mm fans. At any rate, thermal comparisons should settle any question of thermal issues either for Intel or AMD.

I still don't know if my thoughts about case testing are clear. I take issue with the open case, huge cooler testing that they do over at Anandtech. Likewise I take issue with the schizophrenic testing they do over at Toms Hardware Guide. I mean, who in their right mind would put four graphic cards in a small case? I don't really care that much about testing power draw. If electicity is really a concern you could always buy a lower power system with slower memory, 65 or even 45 watt processor and use integrated graphics. But most people are not that concerned about it. Of more concern is whether or not a given case will work with a given system. Generally, everything that people do to increase speed also increases heat. Voltage is increased on the memory, on the CPU, and even on the graphics. Higher clock speeds, more memory, and faster graphics all use more power. We all know that, at various times in the past, thermals were an issue. AMD had K7's before Barton that ran hot, Intel had Prescott which ran very hot and begat the BTX case as a desperate solution. There had been rumors of higher clocked AMD dual and Intel quad core 65nm processors running hot. Of course, now everyone is on 45nm but the top end chips are still rated at 125 or even 140 watts. My results should have much more practical value to people who would like to build lower and midrange systems rather just people at the very top end.

Keep in mind that thermal testing is somewhat separate from performance testing. You can't really begin benchmarking unless you know a given system is reliable. Too often, it seems that reviewers achieve a hasty estimate of maximum clock and then run their benchmarks without really knowing how stable the system is (unless it crashes during the tests). I suppose that and time pressure is why they take so many shortcuts. It takes hours just to run memory stability tests and hours more to run system and stress tests. And, this has to be repeated when trying to find a maximum overclock. Lots of variables like memory voltage, northbridge speed, CPU voltage, base clock versus multiplier all add up to hours and hours of added testing. And this before any actual benchmarks are run. I am confident in the settings on my system. I run the CPU at 3.4 Ghz. I've tested it much higher. I run with auto voltage on both the CPU and NB. I run with the base clock at 200 Mhz and the NB at 2.6 Ghz. I have the memory at 1333 Mhz with CL 7 and 1.545 volts. Auto doesn't work with the memory since auto is 1.5 volts and it will get errors at 1.515 volts with these settings. I'm confident that this is maximum performance for my system. I've tested overclocking the graphics but this isn't really worthwhile since you can get many times better performance without stressing the chipset just by putting in a moderate graphic card like the HD 4650. I expect both the i5 and 965 to show improved performance over my current system.

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.