Bad Chip Test Results

After more testing I've come to the conclusion that I have a bad chip.

These are screenshots from my last test which I think is pretty conclusive. You can click on the images to see the full size.

This is the beginning of the test. Everything is normal here. The voltage and clock frequency are at normal values. This should be an easy test for the i5-750. I also included the Windows CPU Meter, Clock, and Calendar gadgets for extra verification. Note that the CPU meter agrees with OCCT showing both 100% CPU usage and 90% memory usage.

This period is the gap between test cycles. Note that CPU usage has dropped to 25%. Note that this occurs at 10 minutes and 16 seconds into the test.

The most important thing to note here is that the CPU clock has dropped to 1.2 Ghz but CPU activity is still 100%. This is a clear indication of thermal throttling. Note that this occurs at 12 minutes and 19 seconds into the test.

This is the OCCT graph. You can see the large drop at 10 minutes which corresponds to the second screenshot. The smaller dip at 12 minutes is the thermal throttling captured in the third screenshot. You can also see that thermal throttling had been occuring before the 10 minute period between tests.

This chip is definitely bad.

Intel i5-750, Bad Chip Nixes Tests

I don't think these tests were representative; I think the chip is bad.

Below is the original article. I'll have to do a new one after I get the replacement chip.


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I could not get the processor to pass an OCCT Linpack test at 2.9 Ghz. The problem is that the processor heats up quickly to over 72.7 C which is the chip limit. But, when you reduce voltage, the procesor becomes unstable. At 2.9 Ghz the processor gets errors with 1.16 volts. So I tried increasing to 1.18 volts VCORE and cutting the clock down to 2.8 Ghz. The processor is stable at 2.8 Ghz but heats to 75 C. Frankly, I could not get the processor to stay within range higher than 2.66 Ghz with Turbo turned off. I did some screen captures to show this.

The voltage indicated by OCCT on the following images will be slightly less since it drops during testing. When idle, the voltage shows correctly as 1.18 volts.

The maximum temperature for this processor is 72.7 C. With Turbo off, it just stays within the range.

However, with Turbo enabled the processor increases clock and heats up to 77 C which exceeds the maximum temperature. The thing that bothers me is that I'm seeing it exceed its thermal limits with the voltage set at 1.18. With the voltage at the normal 1.25 volts this would be even worse.

We now have our baseline. With the stock cooler, the i5-750 cannot be considered to be overclockable or even within limits with Turbo enabled. This means that the vast majority of people who buy systems with this processor have a marginal configuration at best. Intel pulled the same stunt with its original Kentsfield quads which were also out of range at stock speeds. Anand Lal Shimpi was well aware of this but in true overclocker fashion he simply averted his eyes and pretended it didn't exist. I had hoped the problem had been fixed with the G0 stepping and the lower voltage 45nm Penryns but now we have Nehalem and the problem is back.

There may be some Intel fanatics who will think I'm being unfair to Intel but I tested my X3 720 and PII 965 the same way. The X3 720 is fine with the stock cooler while the PII 965 needs improvement. However, it should be noted that the PII 965 in stock configuration is more than adequate and could even tolerate a mild overclock of maybe 100 or 200 Mhz. So, in stock configuration AMD does what it is supposed to while Intel fails. The next step is to bolt on the heftier Freezer 7 Pro cooler and see what happens.

Intel i5-750, First Look

I now have my Intel i5-750 system up and running. This is the progress so far.

I have three very good processors to compare. I started with a three cored AMD X3 720 in my CoolerMaster Storm Sniper case with an Asus motherboard with AMD 785 chipset and 8 GB's of OCZ AMD gold edition memory (4 x 2 GB's). I never bothered changing to a third party cooler because the stock unit was adequate. I ran it with the integrated graphics which were not too bad but underpowered for games like Dawn of War. The thermal properties of this processor are good enough that I should be able to run it just fine in a small, tighter case with a moderate video card. I have handy a smaller case with neither front nor top fan (only the rear fan) and an HD 4650 video card. However, I do have an upgrade ready for the rear case fan if necessary. I'll probably end up running Linux on this system. The processor is rated at 95 watts TDP.

After the X3 720, I replaced the motherboard with an Asus board with AMD 79X chipset and 8 GB's of OCZ AMD Black Edition memory (4 x 2 GB's). The video was upgraded to an HD 5770 and the processor upgraded to Phenom II X4 965. This processor is the C3 stepping and is rated at 125 watts TDP. I also preferred a third party, Freezer 64 Pro cooler over the stock cooler. The stock cooler, in spite of the copper bottom and heat pipes, still blows hot air down on the board.

I have a second CoolerMaster case, a HAF 922. This has very similar front and top 200mm cooling fans with the same rear 120mm case fan. The box chasis is identical with the same drive bays in front. The power supply is a bit different. This system has a 700 watt CoolerMaster PS compared with the 850 watt Corsair PS in the Sniper case. However, neither power supply contributes to case heating or cooling because they both draw air from the case bottom and exhaust it out the back. My i5-750 is also rated at 95 watts TDP. I suppose the first question people might have is if it draws the same amount of power as the X3 720. No, it doesn't. Even at maxium overclock, the X3 720 barely throws any heat while the PII 965 throws a lot. The i5-750 is in between. It throws a great deal of heat at 3.4 Ghz, much more than the X3 720 does. If I were to make a rough estimate, I'd say the i5-750 must pull around 115 watts. This would put it a little closer to the PII 965 than the X3 720.

I've heard people say over and over that the Intel cooler is poor. It is actually quite a bit better than the stock X3 720 unit which has a smaller fan and no copper core. If the i5-750 really did draw as little power as the X3 720 then the heatsink would barely get warm. But this is not the case. Overclocked to even 3.4 Ghz, the heatsink blows hot air on the motherboard much more like my PII 965 than the X3 720. I'm sure there will be some skeptics who've read some whiz bang review somewhere that claims that is has accurately measured the CPU power draw at some incredibly low figure. Not a chance. The i5-750 undervolted to 1.12 volts still throws more heat at 3.4 Ghz than an X3 720 does at 1.325 volts and the same 3.4 Ghz. The X3 720 and i5-750 are absolutely not in the same thermal class.

So, Intel fudges the numbers? Yes. Does that bother me? No. Keep in mind that I'm not comparing the quad core i5-750 to the X3 720. That wouldn't make any sense because the X3 720 is much cheaper. No, I'm comparing the quad core, i5-750 to the similarly priced, quad core, Phenom II X4 965. The PII 965 is certainly not light on heat and, if the i5-750 can do the same amount of work, it doesn't have to be either. I have a very similar Freezer 7 Pro ready to install so I can at least stop the hot air blowing on the board. I'll add an update after I see how that works. You can see the pictures of the coolers below in my last article.

Note. I haven't switched to the Freezer 7 Pro cooler yet because I'm still trying to establish the baseline with the stock cooler. I have to admit that this is difficult for me. I didn't have any trouble pushing the X3 720 and PII 965 to their limits. And, when I knew what the limits were I accepted them. I ended up with 3.8 Ghz on the PII 965 and 3.4 Ghz on the X3 720. But, I tend to handle the i5-750 with kid gloves. It isn't easy being tough on i5 because doing thermal testing on an Intel Nehalem is like watching an eight year old trying to keep up with teenagers. Simply put, when I started holding the i5-750 to the same standards I used for my AMD processors, the i5 failed. So, I lowered the clock and tried again. I started at 3.6 Ghz then dropped to: 3.5, 3.4, 3.32, 3.154, and 3.078 Ghz without success. I was hoping it would pass at 2.988 Ghz but that just failed with an error. So, I'm trying again at 2.9 Ghz.