Questions about my first i7 860 oc

[CheckMate2010]

Hi I clocked my i7 860 up a few weeks back for the first time. I've now detuned it back to the factory clock but i'll come to that in a second.

factory clock is 2.8GHz with 3.4 at turbo boost

I clocked it to 3GHz with BCLK of 200MHz and Multiplier of 15 and RAM at 1600MHz
(I only clocked it to 3GHz because it was my first oc and just wanting to do and oc to get familiarised with the variables)

before I did it I read some articles that said I may need to boost the IMC voltage.

I decided to go for a high BCLK because I had been told that the ratio of BCLK to RAM is what determines your FSB : DRAM ratio and that the better ratio the beter performance I would get for the sort of computing I do (which is mostly image editing). What is your opinion on that?

when I first changed the Clock speed I uped the IMC voltage a little but it wasn't enough and my pc kept crashing. So then I changed it to auto and it went from 1.16v at factory clock to 1.35. I think this must have been mostly due to having such a high BCLK. The maximum IMC voltage is 1.7 but 1.35 is still a significant increase of .2 v does 1.35 seem high to you?

everything was running fine with my overclock and has done for a month or so.

However I tried a stress test with prime 95. And yes I'm a newbie and considering a clock of 3GHz is only slightly over the factory clock and less that the factory turbo boost clock I thought it might be okay on the stock heat sink. It certainly wasn't it crashed. And I'm presuming it was over heating that caused the crash because I think the temps got up to 85 - 90 degrees, not good. So I quickly stopped doing that. From then I just used it for my every day computing and it been running totally fine.

I have now detuned it back to factory settings and have done 5 and a half hours of tests in prime 95 with no errors and an average temp of 77 degrees with a maximum of 80. Again still with the stock heatsink.

And now I have just ordered a corsair H50-1 water cooler. When it arrives I plan on doing a more serious oc. I'm wondering if I might be able to reach the 4GHz mark, what are my chances?

cheers,
Duncan

 

[Lmeow]

When you increase your BCLK, it increases your RAM speed as well. For example, with a 200MHz BCLK and your FSB : DRAM ratio set at 2:8 you will have your RAM running at 1600MHz, which just means faster memory performance. However it may be better to have lower latencies than higher frequencies.

I'm not sure but if IMC counts as VTT then the maximum recommended voltage is 1.21V by Intel and 1.35V is quite a bit over the maximum.

Also I suppose your temps are average with the stock cooler, but remember if you decide to overclock later on it's best to stay below 75°C under full load, Prime 95.

 

[CheckMate2010]

Thanks for your reply Lmeow!

Thanks for you tip about the VTT i've tried doing a bit more research on this but am still a bit confused. Apparently the VTT is memory controller, QPi and L3 cache voltage. I can't see a dedicated voltage for IMC in the i7 800's data sheet so I think you are probably correct. My system has been running fine though so I don't think I did any damage when it was over clocked but I shall be more prudent in future!

Also thanks for tip about staying under 75°C with prime 95 it's good to have something to work to!