Overclock.net › Member Blogs › Core I7 920 Overclock 3 5 Ghz Part 2

Core I7 920 Overclock 3 5 Ghz Part 2

Note: I wrote this post on Tuesday, but I am just now getting it published. I have a follow up post, and I'm just going to post both of them at the same time to catch up.


I spent the past weekend tweaking my overclock. The list of goals started with this from my previous post…

“My list of ideas includes reducing the CPU voltage even further, changing some of the other voltages (memory and QPI) to manual values and then finding their lower limits, and turning off some of the energy management features of the motherboard to see the effect.”

Before I went any further, I saved my current stable bios settings into a profile. This proved to be a pretty smart move. The rest of this post is a failed attempt, so you won’t learn anything from here except what not to do. It might be a useful learning exercise for other newbie overclockers and good humor for everyone else

I chose to continue my quest by changing two key voltage settings from the values that "auto" had assigned to manual values. I lowered the memory voltage from 1.6v to 1.5v, because I was running the memory at its rated frequency of 1333 MHz and it should be able to do that at stock voltage. I lowered the QPI/VTT voltage to 1.34v from 1.42v, because 1.34v was the highest setting that did not give a "pink warning" when it was assigned.

While I was poking around, I also took the memory timings off "auto" to assign them manually. CPU-Z had reported that my memory was running at 9-9-9-24. I was very sure I could do better than that. The bios had recommended values of 8-8-8-20, so I thought that was a good start and keyed these values in leaving the other settings on auto.

I re-booted successfully, and my motherboard voltage LED's indicated that I had changed the voltages for the better. I checked the memory in CPU-Z, and my target timings were now being reported as the actual. So everything must have worked - so far so good. I decided to run OCCT for an hour and see what happens. I started the program and it gave me a BSOD in two seconds. Obviously not stable!

The newbie mistake…? I made so many changes that I had no idea what caused the instability. Was it setting the voltage too low, and if so which voltage? Or were the memory timings the cause?

I had a suspicion that it was all of the above. I got a BSOD error 124, which usually indicates low QPI/VTT voltage. So I realized I needed to address that right away. I decided to restore to my previous profile settings, and I posted on Mushkin’s forums for advice on memory timings before making another attempt on another day.


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