Hi all, Taking my first steps into OC, and have a couple of questions... I've managed to get what seems to be a stable OC of my i7-870 in a fairly simple way: multiplier is locked at 22, BCLK at 150 and vcore at 1.35v, so a steady 3.3GHz. However I'd like a little bit more (3.8-4.0GHz) but am unsure how to proceed - I need to crank the BCLK value up but whenever I do (above 150) I get a very unstable system, which is unlikely even to boot. I'm aware that I need to change other values (memory voltage and timing?) as the BLCK increases but I'm not sure which so I thought I'd ask first. HT/Speedstep/C1E/Turbo all disabled. TIA!

When you raise the BCLK you raise the memory clocks too.What memory are you using and what is it rated at? what speed and timings are you running it at with a 150 BCLK?Are you following some OCing guide in particular?

I'm not entirely sure what memory I have (I bought the system fully built). Is there any way of finding out without opening up the case? Not following any particular guide, no.

CPU-Z SPD tab: rated speed and timingsMemory tab: current RAM speed and timings Are you not stress testing, and monitoring Vcore and temperatures?Do you have a CPU aftermarket cooler?

Ah yes thanks, I have CPU-Z. At work at the moment so I'll run CPU-Z when I get home and let you know.

My former setup was a I860 with a P5P55D mobo and 6Gb OCZ 1800 mhz memory.With a Vcore of 1.46 I was able to run the pc at 4.25Ghz having thge memory run at 1600 mhz 6/6/6/25.Thyis sysem I used for 3 years and now my son has it ( downclocked it though ).

CPU-Z SPD tab: rated speed and timingsMemory tab: current RAM speed and timings Are you not stress testing, and monitoring Vcore and temperatures?Do you have a CPU aftermarket cooler?

Ok, here is my CPU-Z report in its entirety. Been using Prime95 for stress testing, RealTemp to monitor vcore and temps. CPU cooler is stock I think but I have a decent Antec case with 1x220mm and 2x120mm fans.

And what were your temps like while running Prime95?On the stock cooler you won't be able to overclock too much You are running your RAM at 1200MHz 8-8-8-21To go farther on the BCLK (apart of upgrading the cooler) you'll need to set your RAM timings to 9-9-9-25 or 10-10-10-28

Can't remember the temps off the top of my head; I have them at home so will post them later. Although I'm not using a specific guide, this has been rather useful to start. It mentions that along with upping the BCLK I should be upping the QPI/VTT voltage and changing the memory multiplier. Is that the case?

If you can't remember your temps you didn't pay enough atention to them. OCing with the stock cooler you should be very careful with thatMax core temps should be 80ºC under full load (stress testing, not gaming or anything like that) Max Vcore (in CPU-Z / full load) 1.4VMax Vtt also 1.4V (in BIOS, ) Vtt can help with stability, especially at higher CPU & memory clocks, but get a proper cooler before you keep OCingThe RAM multiplier is important. You can't run your RAM (much) faster than what it's rated for. When you raise the BCLK, RAM speed increases, so you may need to lower the RAM multi and/or loosen the timings to keep your RAM within specs

Just did a quick test and it went up to 86 pretty quickly. Time to knock the voltage down I think!

Voltage at 1.3 now seems fine. Would my next step be to change the memory to 9-9-9-25 or 10-10-10-28 to be able to successfully increase the BLCK? Any idea of what a realistic max OC would be with the stock cooler, or should I just be happy with 3.3GHz?

Voltage at 1.3 now seems fine. Would my next step be to change the memory to 9-9-9-25 or 10-10-10-28 to be able to successfully increase the BLCK? Any idea of what a realistic max OC would be with the stock cooler, or should I just be happy with 3.3GHz?

Your max OC with the stock cooler will be determined by your temps. Keep them below 80ºC in Prime95With a good cooler you could get to 3.8 - 4.2GHz, depending on the chip. Most do 4GHz