Core i7 920 overclock voltage. Is 1.475 to much?

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robothunter

Limp Gawd
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Jan 19, 2008
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I just built my new computer and have been playing around with overclocking it. It is also my first water cooling setup. In order to get 4.4GHz stable I have to use 1.475v core and 1.4v QPI. After running LinX my highest temp spiked at 79C. So I feel like my new water cooling setup is doing its job. But is that to much voltage for everyday use?

I can also run stable at 4.2GHz with only 1.35v Core and 1.3v QPI and a max temp of 65C. I have spent so much time tweaking my voltages at 4.4GHz that I haven't had a lot of time to tweak it at 4.2GHz so I might be able to get that voltage lower.

I have experimented with up to 1.9v PPL, 1.4v IOH and 1.4v ICH. I have also tried loosening my memory timings. None of that seems to make any difference.
 
Well, both of those voltages are out of spec for 24/7 use if you ask Intel. I personally feel that heat kills processors more than voltage. If it were me, hell yeah I'd run it at that. Shit its the reason you spent so much damn money on that watercooling loop in the first place right? So enjoy it and worst case scenario you'll need to buy another cpu in a year, which you would probably do anyways :)

My $.02
 
I was reading some other forum posts and someone mentioned running LinX overnight if your power bill could afford it. It got me thinking because I live in NYC and I pay a lot for electricity. I hooked up my P3 Kill-A-Watt to my computer and took some readings. At 4.4GHz I am using 485w under load. At 4.2GHz I am only using 390w under load. 200MHz isn't worth and extra 95w of electricity.
 
I think my system is running 24/7 at 1.475 ... running a problem at the moment so I can't double check. The voltage is definitely bumped up, but not sure to what off hand.

My philosophy is with BlackDragon24 although my apps do not stress the system as LinX, but they do nearly peg all of the bars in Task Manager for many hours if not days. And, yes, I am sure that I take a hit in the power bill but I use my computers for consulting income. Also at night or I am away & I don't have some long running program they are shut off.
 
Personally I would pull back to 1.35v and go with 4.2GHz. Still I would GUESS that you could run that 4.4GHz with 1.47vCore for 4 or 5 years before seeing issues.
 
Thanks for your opinions. I'm going to run it at 4.2GHz and see if I can tweak the voltages a little.
 
I would qualify my post with "if you can't afford to pay, don't play" ... meaning if you do want to minimize your chances of a CPU failure, at be least somewhat conservative with upping the voltage.:)

I am planning (well thinking really hard about) to get a hexa-core when available, so I have just been looking to see how much I can squeeze out of my i7 920. Then setting it aside for ... awhile.
 
I am personally at 1.35V and hitting 4GHz, and I think this might be the sweet spot. If I move to a cooler house (this house has very terrible insulation and in Central Florida that means summer time gets expensive as well as hot, so I don't really want to push it to only have to bring it back in a couple months). If I had a D0 I guess I could go faster at the same voltage/temps but oh well. 4GHz is blazing, and I am happy with it.
 
Personally run mine @ 4.2 @ 1.35 ... 24/7 :D

I didn't want to push it to much higher and I only cool it with a H50 so I am happy 65*c max load
 
I was quite susprised to see that the Absolute Max Vcc in the intel datasheet is back up to 1.55V (the 45nm cores where 1.45 , 65nm cores 1.55)

Table 2-6. Processor Absolute Minimum and Maximum Ratings

Symbol Parameter Min Max Unit Notes1, 2
VCC Processor Core voltage with respect to VSS -0.3 1.55 V
VTTA Voltage for the analog portion of the integrated memory controller, QPI link and Shared Cache with respect to VSS — 1.35 V 3
VTTD Voltage for the digital portion of the integratedmemory controller, QPI link and Shared Cache with respect to VSS — 1.35 V 3
VDDQ Processor I/O supply voltage for DDR3 with respect to VSS — 1.875 V
VCCPLL Processor PLL voltage with respect to VSS 1.65 1.89 V

edit:
Note - this is from a personal copy of the i7 datasheet I pulled from Intel.com on release date of the cpus, I have not checked for updates/corrections/changes.
 
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Ya I think these 920s can handle a lot of pain and I know Intel knows that too and knows people are pushing them
 
I run my 920 D0 at 3.6GHz at 1.128v. An extra 400MHz was not worth pushing the vCore up to me. This thing is ROCK SOLID and I could not be happier with it.
 
you're never going to see the real world benefit of an extra 200mhz. do a few benches/screenshots @ 4.4 to show you were there, then make ur proc & wallet happy & run @ 4.2 24/7
 
I didn't and still can't tell a difference in anything I do from stock to 4.2
(noticeable in benchmarks but not in anything "real")

That same as putting a cold air intake in a honda and thinking you just installed an extra 40hp :D


But I didn't buy all this junk to run it stock ;)
 
Yea, I encoded a Blu-ray at 1080p. It took 3:45 at 4.2GHz and 3:29 at 4.4GHz.. Not that big of a difference.
 
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