Hi Guys, I have a new build as below, with a target of a 4.8GHz o/c. I am really struggling in that I have it @ 4.738 (103 * 46) but it will either fail OC on boot or BSOD on loading prime95 if I go higher. It does not seem to be heat related and I have tried various combinatons of BCLK and multiplier with out any joy. I cannot really go beyond 1.35V as my water loop is not up to the job (handling 2 GPUs as well) and CPU showing 70C+ on one of the cores. Could really use the help on a couple of questions: Is it better to increase BCLK or multiplier? It does not seem to make a differnce so far in the total frequency is what is failing the o/c. Is there a combination of VCCSA/VCCIO overvolt that is worth trying. I do not know enough about them to know which would make a difference Just to add something positive - you can get a triple rad 120 + fans into a Cosmos S; BeQuiet Silentwings are brilliant; if you try to dry your SSD with a hairdrier and the hairdryer cuts out leave for 10 mins it will be OK (SSD was OK as well); a dremmel polisher can go through tungsten if you push hard enough; when building a water loop - work out how you are going to get the water into the fillport first! I have a photo journal of the whole thing, but embarassed to post give the extreme quality on the forum. ----- Asus P8P67 Pro Intel Core i7-2600K, 4733 MHz (46 x 103) NVIDIA GeForce GTX 570 (1280 MB) x 2 in SLI OCZ Vertex3 SSD (223 GB) Samsung F3 x2 (RAID 0) G Skill F3-17000CL9 4GB Custom water loop (GPU + CPU)
CPUs can vary considerably in their OC mileage. Its possible that this is just the best your CPU can go. 4.7GHz is still a beastly speed for a hyper-threaded quad core.
Yeah sounds like that's the limit for that chip mine only reaches 4.4 GHz before it will blu screen after about 18hrs of prime at any higher.
my 2500k needed about that voltage just to reach 4.5ghz. you need more voltage (and from the sounds of it, more cooling) to go higher. FYI, OCing sandy bridge with the base clock is a very bad idea. base clock controls everything on these boards, including your SATA controllers, and overclocking those can result in corrupt data. ive also heard rumor that its hard on the CPU, but havnt seen any facts supporting that claim.
i had exactly the same problem. just hit a brick wall at 4.7. cooling has nothing to do with it. ive even tried pumping 1.5v through it but it makes no difference. hitting 55c prime for 24hours. decided to give up at that speed as its more than enough and concentrated on running it at the lowest possible voltage at 4.7. got it down to 1.29v stable.
OK thanks guys, looks like I will have to live with 4.7 and move onto the GPUs. I will taken on board the BCLK advice and see if I can get 100 x 47 stable.
It seems that when your Sandy Bridge hits the threshold, there is nothing you can do even with the best cooling and power management in the world: http://hardforum.com/showthread.php?t=1578110
Just discovered something counter intuitive that helped me OC further. LOWER the PLL voltage as far as it will go. Mine went as low as 1.395V. CPU runs cooler and for some strange reason can OC further.
