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- Date:
- Thursday , November 13, 2008
- Author:
- Kyle Bennett
- Google +1
Intel Core i7 920 Overclocking and Power
We follow up on our Intel Core i7 coverage and give you a look at just how much power you are going to need when overclocking that new Core i7 model 920 from 2.66GHz to 3.8GHz.
Introduction
We have done a lot of Intel Core i7 coverage around [H] in the last few weeks. i7 and FarCry 2, i7 920 Overclocking and Heat, i7 Application Results, and i7 Synthetic Benchmarks just to name the “i7” articles. Today’s coverage is a follow-up to the OCing and Heat article linked above. We were showing Intel Core i7 overclocking and just how easy it was, but also just how much heat was being produced. The higher-than-what-we-are-used-to i7 core temperatures begged your question, “How much power is that thing using?” Quite frankly we were wondering as well so we set out to answer that question.
Intel Core i7 Overclocking & Power
We are going to show you how the power usage of an Intel Core i7 system scales as we move up BCLK MHz as well as vCore and QPI bus voltages from stock settings. These are the two primary voltage knobs you are going to have to tweak in order to get your Core i7 920 stable. And ours has been rock solid at 3.8GHz. While I would like to say, for the sake of e-peen, that 4GHz has been bulletproof for us, it just is not the case. We only have a single 920 sample currently and it is just not stable at 4GHz on air or ambient water cooling, no matter the tweaking we have done on either the ASUS P6T or ASUS Rampage II Extreme.
We attempted to run our system as lean as possible. In our video and graphs below, the hardware represented is an Intel Core i7 920 2.66GHz processor, an ASUS Rampage II Extreme motherboard, 3Up x 2GB of Corsair DDR3 model TR3X6G1600C8D (cool video here showing 12GB at DDR3-1600), and an Intel 80GB “SSD” Solid State Hard Drive. The video card is an NVIDIA 6200 TurboCache GPU based card. All backed up with the incredibly efficient Thermaltake ToughPower 1200W PSU.
All processor power features have been disabled. StepStep or Turbo turned off.
Supporting Material
Our “crazy” voltage settings mentioned in the video as well as a quick 4.2GHz screen shot from what is mentioned in the video. Yes, CPUZ identifies this CPU as the “940” but according to Intel it is a “920.” The motherboard BIOS identifications on three separate motherboards state 920 as well. The CPU is marked “Intel Confidential.” We are surely going to be following up with retail products purchased from “store shelves” the same as you would buy them.
As the BCLK scales, so does the DDR3 speed. With the two motherboards we have tested with the Core i7 920 you can choose from 1066MHz DDR3 which is an 8 multiplier (8*133MHz BCLK = 1066) or you can select a 6 multiplier (6*133MHz BCLK = 800). Those multipliers are specific to the 920 whereas the 940 and 965 have higher multipliers exposed in the BIOS we have seen. At our 190MHz BLCK shown you can go with either 8*190=1520MHz DDR3 or 6*190=1140MHz DDR3. We elected to go with the 1520MHz DDR3 speed. If you do not push your RAM overclock hard and use the 6 multiplier, you will not need to scale the vQPI as shown in our “actual” chart. But of course most of you will want to. 
Discussion
Join our HardForum discussion about this article.
Video Corrections & Additions
BenQ is pronounced “Ben-Que” not “bink” as I did in the video.