i7 920 @3.8ghz hitting 100c on stress tests HELP Please

[JJJ]

Hi all,

When I run optimized defaults my idle temps are 43, 40, 42, 40 C and at full load I hit 83c, running linX, as reported by realtemp.

When I run an overclock @3.8Ghz (21x181), all settings CPU, MCH/ICH set to NORMAL, 1.64 Dram Voltage timings 8-8-8-24, everything else is set to AUTO, my idle temps are 46, 43, 45, 43 C, and at full load my cpu hits 100c, running linX as reported by realtemp. My CPU core voltages are 1.047 to 1.280, idle to full load. I've tried taking off the side panel of my Addtronics Addtronics ET7896A case and temps are lower by 3 to 4c so I don't think its an airflow issue. I've reset my heatsink and reapplied Arctic Silver II (Don't know if this older TIM, is an issue) twice or thrice. I have a tube of IC Diamond 7 Carat Thermal Compound en route to see if that makes a difference. Anyone have any insight on how to lower my OC full load temps?

[Grnkjr0]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

What were your temperatures using the stock CPU cooler? It is most likely you missed something when installing your new cooler.

[demonsavatar]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

For comparison, I gave JJJ my BIOS settings and his multiplier/voltages and his CPU cooler are the same as mine, but I never hit greater than 90C running stress tests for many hours. At stock values I don't see above 80C. Considering we have the same cooler and all, I might suspect that his CPU or heatsink may not be as flat or smooth as mine and may require lapping.

Regardless, if you cannot decrease those temperatures below 90C, I would recommend lowering your overclock unless you are not under max stress often. I do calculations so seeing 90C+ for hours at a time would be bad. If you are doing something similar or gaming for multiple hours you may want to decrease it.

[JJJ]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

What were your temperatures using the stock CPU cooler? It is most likely you missed something when installing your new cooler.

I never used the stock cooler.

[aquax]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

your max safe 90c, don't go more than that.

[profJim]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

Your cpu heat sink might not be properly seated.
Check your heat sink fan's speed and air flow direction.
Sometimes it's the simple things that cause problems.

[JJJ]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

I slightly adjusted the heatsink position on CPU, reset all case fans to positive air flow and and took the CPU multiplier down to 19 x 184, all other settings the same, and I momentarily hit 90c on one core (best result after trying several different multiplier combos). My heatsink fan runs at 1596-1600, which is its max. My conclusion is that I am either not getting enough cool air to the heatsink when the CPU runs at full load or the heatsink is not drawing enough heat off the cores at full load. Outside of making any case mods, I hope that the IC Diamond 7 TIM will improve the heatsink's ability to draw heat off and away from the CPU.

[viper7lv]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

JJJ you just hit the nail on the head in your last response. Your heatsink fan is not able to supply enough air flow across the Ultra 120 to cool your CPU under load. I would guess that the CFM air flow of the fan you have is between 45 and 58 CFM at max speed of 1600, that is good for Idle but not for cooling any kind of load you put on the CPU.
I have the Ultra 120, with an i7 940, at 4.0ghz, my Vcore is 1.375, and my QPI is 1.425, so my voltage to my CPU are much higher then you are using for your CPU. My Idle core temp are the same as yours, but at load my core temps never go above 70C, that using Prime95 for about 4 hours….
You need to get a new heatsink fan with a higher air flow. The fan I use is the CoolJag Everflow 120mm, that has an air flow of 110 CFM at 2400RPM, I use the PWM feature in the BIOS, so that the CPU controls the speed of the fan, it runs about 1500 at idle and around 2050 under load. Hope this helps you

[artdrivers]

http://images.tweaktown.com/imageban...2.12_(ENG).pdf

[JJJ]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

http://images.tweaktown.com/imagebank/Core%20i7%20920%20oc%204G%202008.12.12_(ENG).pdf

That .pdf was one of the first things I looked at when considering building this system. I'll take another look...

[JJJ]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

JJJ you just hit the nail on the head in your last response. Your heatsink fan is not able to supply enough air flow across the Ultra 120 to cool your CPU under load. I would guess that the CFM air flow of the fan you have is between 45 and 58 CFM at max speed of 1600, that is good for Idle but not for cooling any kind of load you put on the CPU.
I have the Ultra 120, with an i7 940, at 4.0ghz, my Vcore is 1.375, and my QPI is 1.425, so my voltage to my CPU are much higher then you are using for your CPU. My Idle core temp are the same as yours, but at load my core temps never go above 70C, that using Prime95 for about 4 hours….
You need to get a new heatsink fan with a higher air flow. The fan I use is the CoolJag Everflow 120mm, that has an air flow of 110 CFM at 2400RPM, I use the PWM feature in the BIOS, so that the CPU controls the speed of the fan, it runs about 1500 at idle and around 2050 under load. Hope this helps you

The fan that came with the TRUE is the Thermalright TR-FDB-1600 it has an airflow of 63.7 CFM. I didn't even think about this being an issue--duh. I swapped it out with a 2000rpm Evercool fan that has an airflow of 79.14 CFM and just ran the same test as my last and the highest core was 82c. I think you are right the solution is getting a 110 CFM fan or higher. Anyone else care to chime in on this? Any other fan recommendations?

[demonsavatar]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

The fan that came with the TRUE is the Thermalright TR-FDB-1600 it has an airflow of 63.7 CFM. I didn't even think about this being an issue--duh. I swapped it out with a 2000rpm Evercool fan that has an airflow of 79.14 CFM and just ran the same test as my last and the highest core was 82c. I think your right the solution is getting a 110 CFM fan or higher. Anyone else care to chime in on this? Any other fan recommendations?

I am using the fan that came with the TRUE, now that you mention that I did think about replacing the fan at some point. I may do so now. I hate noise but if I get a variable fan it should only kick in when necessary.

It's a bit disappointing that Thermalright would include a fan that would not use the potential of their excellent heat sink design.

One more note, did you check you installed the heatsink in the optimal orientation? The heatsink works best when it is installed horizontally across the CPU, such that the length of the heatsink hangs over the ram slots. It's only a problem if you have ram with finned heatsinks that stick up.

[JJJ]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

I am using the fan that came with the TRUE, now that you mention that I did think about replacing the fan at some point. I may do so now. I hate noise but if I get a variable fan it should only kick in when necessary.

It's a bit disappointing that Thermalright would include a fan that would not use the potential of their excellent heat sink design.

One more note, did you check you installed the heatsink in the optimal orientation? The heatsink works best when it is installed horizontally across the CPU, such that the length of the heatsink hangs over the ram slots. It's only a problem if you have ram with finned heatsinks that stick up.

I tried it vertically with the FAN on either side of the heatsink and horizontally with the fan blowing up. I found that it performed worse horizontally--but I only tried it once in the fit I've been in trying to get my temps lower. Did you receive the same FAN as I with your TRUE?

[viper7lv]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

The Thermalright fan that came with your Ultra 120 was and is intended to be use on Intel and AMD CPU’s that are being run/used at their stock settings only. The fan was not designed to handle the cooling air flow needed when a CPU is being overclocked, as you are doing with the 920. Yes, it may be able to handle the overclocked CPU cooling at idle, but once any kind of load is placed on the CPU your temps will go up drastically.

[demonsavatar]

Re: i7 920 @3.8ghz hitting 100c on stress tests HELP Please

I tried it vertically with the FAN on either side of the heatsink and horizontally with the fan blowing up. I found that it performed worse horizontally--but I only tried it once in the fit I've been in trying to get my temps lower. Did you receive the same FAN as I with your TRUE?

I guess any defects in the CPU or heatsink would override a general statement that it works better in a certain direction. When X-bit labs compared about 12 coolers, they found that the horizontal orientation was better for most, if not all of them and they claimed it was because of the location of the cores on the silicon. And yes, I also received the TR-FDP-1600 fan which is rated for ~63 CFM.

The Thermalright fan that came with your Ultra 120 was and is intended to be use on Intel and AMD CPU’s that are being run/used at their stock settings only. The fan was not designed to handle the cooling air flow needed when a CPU is being overclocked, as you are doing with the 920. Yes, it may be able to handle the overclocked CPU cooling at idle, but once any kind of load is placed on the CPU your temps will go up drastically.

I find that hard to believe since these coolers are meant for enthusiasts and designed for overclocking. Also, the 64 CFM the included fan pushes is much higher than stock Intel cooler for the i7 920 which I think only pushes around 40CFM. The TRUE and many other higher end heatsinks scale well with higher CFM fans so pushing it up closer to 100 CFM may help a lot.

Now to decide which fan to buy....I am leaning towards the Cooler Master Y720CCD-25K1-GP which has variable speeds and can push up to 109 CFM at max and also run quieter at idle! The included Thermalright TR-FDP-1600 fan is always running at 1600 RPM.

Update: Eh scratch that Cooler Master, I guess I should be looking for a fan with PWM control?