Voltage/Temperature when overclocking i7 920?

Phopedush

Junior Member
Jan 24, 2009
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I'm running a new 920 system overclocked to 3.2GHz, and the temps are a bit higher than I was expecting. I'm not sure if I'm doing something wrong, or if these temps are actually in the correct range. I'm new to this and unsure what to tweak.

Specs:
Core i7 920
Thermalright Ultra 120 Extreme heatsink w/ single 120mm fan, arctic silver 5
Lian-Li PC-A71A
Gigabyte GA-EX58-UD3R
3x1GB G.Skill DDR3-2000 (PC16000)
EVGA Nvidia GTX260
Windows XP 32-bit

With everything at stock speeds/voltages (turbo enabled, so 2.8Ghz), the cores idle around 30-35C. With prime95 running for half an hour, they eventually would reach 55-65C. I've built loads of PCs, but this is the first one I've overclocked, so I opted to let gigabyte's included easytune program handle it for me. Using that app I bumped the cpu up to 3.2Ghz (turbo disabled), and the ram up to 1920Mhz. I allowed the app to handle voltages automatically, and core voltage ended up at 1.328V.

Upon reboot, idle temperatures are in the 39-44C range. I ran prime95 for about half an hour, and killed it when core 0 reached 80C. The final spread was about 75-80C. I took a screenshot halfway through this process, with coretemp, CPUZ, and prime95 open: here. Temps seemed to steadily rise throughout the test, without ever really reaching a peak.

So, my questions are these: First, do these temperatures seem reasonable for such a minor overclock with a monster heatsink? If not, where should I start? What CPU/Dram/etc voltages should I be using? Any other suggestions/comments/questions welcome.


 

yh125d

Diamond Member
Dec 23, 2006
6,907
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Try reseating the heatsink. It may be loose, or you might need more/less TIM (grease)

You may even need to lap your heatsink. Ultra 120s are known for having a pretty crappy contact surface
 

Duvie

Elite Member
Feb 5, 2001
16,215
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Yeah I agree...I would be surprised that at 1.328v the tRUE120 cant keep this thing in the 60's still.....

What 120mm do you have on it....sufficient cfm? I use antec tricool's on high....I think they are 83cfm fans....I know there are some 120x38mm fans (loud) that with do over 100cfm
 

Phopedush

Junior Member
Jan 24, 2009
4
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Fan is a 1600RPM fluid bearing that came with the heatsink, 67.x CFM. Fan is mounted so it is pushing air through the heatsink, with another 120mm case fan venting the exhaust on the other side.

This is actually the second heatsink I have tried on this cpu - the first was a thermaltake V1, which I found to be totally inadequate, reaching temps of 75+ at stock voltage/clock during prime95. I reseated that one multiple times in an effort to improve temps, never with any results. The Ultra120 actually improved things significantly, to the point where I was comfortable enough with stock temps to try an overclock.

Im not opposed to reseating this thing, but that takes a lot of time, so I want to exhaust all the options first. If no one has come up with anything by tomorrow afternoon i'll strip this thing down and seat it again, but I don't expect anything to change. Any other ideas in the mean time?
 

Phantomaniac

Senior member
Jan 12, 2007
268
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At only 3.2Ghz, I don't see you needing near that much voltage. I've got my i7 at 3.5Ghz on stock 1.2v. You should at least be able to back your voltage down to 1.25 if not more.
 

palladium

Senior member
Dec 24, 2007
538
2
81
I got mine @ 3.15GHz at 1.104V, I can warm boot with 3.35 ( 160*21) at the same voltage - cold boot wouldn't work thansk to the stupid BIOS bug.
 

Phopedush

Junior Member
Jan 24, 2009
4
0
0
Thanks for the advice. I just used easytune to completely reset everything to stock, then retried the overclock from bios without changing any voltages. Currently @ 3.2HGhz / 1.168V. Will report back once I've tested it in prime95.
 

Phopedush

Junior Member
Jan 24, 2009
4
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Wow, that made a hell of a difference. In the same amount of time it took to reach 80C under prime95 last night, The hottest core barely reached 63C today. Looks like voltage was the problem.