Overclocking my i7 950

[Anifinity]

Hey [H] members,

I have been browsing the forums for many years but haven't really posted much. I have decided I would like to try overclocking my i7 950 + Asus Sabertooth X58 I have had for several years.

I have read a bit about what needs to be done, including the [H]review of this specific board but I haven't had the luck that others are seeing.

First and foremost, here's what I have to work with.

i7 950
Asus Sabertooth X58
6GB Corsair TR3X6G1600C9 (3x 2GB), 9-9-9-24 @ 1.65v
Corsair HX750w PSU
Antec Kuhler 920 closed loop cooling

First thing I started with was using the Sabertooth's built in auto overclocking utility which automatically adjusts the settings to accomodate 3.73ghz. This ramped my QPI voltage to over 1.43v which seemed too high for my liking, though the system ran fine for several days.

I then moved onto a more manual approach.

My target overclock (if at all possible) is as close to 4.2ghz as I can get. The chip runs hot so I would like to keep temperatures under 75C at load if possible as I would like to keep the CPU another year or so.

I started by adjusting the bclk to 200 with a 21x multi. This gave me exactly 4200mhz for the overclock. This setting bumped my 1600mhz memory to 1603mhz, which is pretty close to its rated speeds. I left the timings at 9-9-9-24 and manually set the voltage to 1.65v

The first time around I manually set the uclk frequency to as close to double the memory speeds as I could which ended up being 3208mhz. I left the QPI data rate as auto.

At this point I figured all that was left was to play with the voltage settings for the CPU and QPI. Here is where I am stuck. I can't seem to find a voltage setting that works.

I tried leaving the CPU voltage at auto along with the QPI voltage to auto and this will allow my computer to boot into windows just fine, however CPUz shows my CPU voltage has auto adjusted to over 1.4v and the temperatures under p95 testing load are averaging 85C which is too hot.

I have also tried a few manual setting between 1.25v and 1.35 v on both QPI and CPU voltage, however I always end up with blue screen 5 minutes into p95 testing.

Any tips on what I am doing wrong, or is it justa case of playing with voltage?

Thanks.

 

[martinje]

Thats a high OC for the I7-950 if you have Hyper Threading and Turbo on. The best I could do was 4Ghz on mine with HT and Turbo on. If you disable those, you might see the 4.2Ghz your looking for. Right now Im at 3.8 Ghz with HT/Turbo on and under Lynx it gets to 82C. Dont remember my voltages but once I get home Ill post them to see if it can help you. My specs are on my info.

 

[Tsumi]

I highly doubt you can keep the temps in check at 4.2 ghz. I had a 920 D0 (essentially the same as your processor with a lower max multiplier), and under a full blown watercooling setup, it will peak over 80 C at 4.2 ghz.

Too high of a QPI voltage can lead to instability as well as too low QPI. For my 4.2 ghz overclock, my QPI voltage only needed to be 1.3-1.35.

How about your PLL voltage? You need to set that to something like 1.88 to keep your BCLK stable.

For reference, my CPU needed about 1.31 vcore in order to be stable at 4.2.

 

[djoye]

I've been running mine at 4.2GHz for a while now. I initially tried for 4.0GHz because I thought that was reasonable but the damn thing won't run at a 20x multiplier; it passes benching but craps out in games so I moved up to 21x multiplier and it was fine.

Mine is setup like this:
200×21
EIST and C1E disabled (maybe I can enable C1E?)
Turbo disabled
HT enabled
QPI x36 (I've read that QPI must be at least 2×Uncore)
Uncore x16
Memory SPD 8.0
PCI-E locked at 100MHz
CPU 1.34375V
QPI/Vtt 1.375
DRAM manually set 1.66V (I think in my BIOS the option was 1.64 and 1.66, no 1.65!)

Everything else is AUTO.

I use 5 passes of IntelBurnTest (same as Lynx I think). I think it might've hit 80C or close to it but it passed and it's stable encoding video and playing games. On heavy usage it might hit low-70's; I encoded a video and it was using most of the CPU and hit 74C. It idles around 40C depending on room temps. I'm using an H70 to cool it.