I've Just run Prime95 for about 8 hours and everything works stable at the following settings:
All other BIOS settings left on Auto.
These settings give the CPU a speed of 3.3GHZ. However, I recently tried to get it to 3.5GHZ at an FSB of 389 and Vcore of 1.40 - and the computer wouldn't boot windows or the BIOS - I had to reset the mobo.
I am slowly trying to get the CPU to 3.5 or 3.6 though (depending on temperatures). What settings do you recommend I go for? Should I also be adjusting other BIOS settings (such as DRAM frequency or North bridge voltage) or leaving them on Auto? I'm using an ASUS P5Q PRO motherboard and a Scythe Mine CPU cooler.
If it helps, my PC specs are:
Intel Core 2 Quad Q6600 G0 CPU
ATI 4870 GPU
ASUS P5Q PRO Motherboard
OCZ DDR2 800MHZ 4GB RAM
Antec 900 Case
Corsair 650W PSU
Scythe Mine CPU Cooler
In my opinion, when going above 3.0ghz with a q6600, everything should be manually tweaked to minimize overvolting anything. Most motherboards will throw extra voltage, for the sake of stability, which will create more heat.
You need to a least set the pci-e to 100 because when you raise your fsb, your overclocking the system bus, and your pci-e slot will go along for the ride.
I would set a low multiplier (set it to 6), then try to establish a stable fsb.
So slowly work your fsb up with a 6 multi, until you reach the number you are looking for. Test those settings before resetting the multiplier to 9. This way your only overclocking one thing at a time. Much easier to problem solve. Sometimes adding some voltage to the north bridge is needed when using a high fsb. I don't think yours is too high, so a minor tweak of +1 might do it. Or you could be experiencing "fsb holes." Are you slowly moving up, or are you going in 5 to 10 increments or more. I once couldn't boot at 340fsb, but could at 339.
Also, have you set the ram timings and voltage? You might be able to get away with defalut freqency, But I would definitely set the proper dimm voltage.
^ Agreed. It took me 1.750 to hit 4.0. I think that is a little high for a VID of 1.2250, but it seems pretty stable...maybe drop it a little for temps. Its good to find out what it runs stable at, then start dropping voltages a little and retest for stability.
Also, as recommended by sportsfanboy, RAM should be set to timings like 6-6-6-15/18 and bump the voltages up to like 1.9 to 2.0...just don't go over the max your RAM is rated for...2.1 is about as high as high end memory handles...most others are 1.8-2.0v.
Try a multiplier of 8x and bump your FSB using that.
Getting a bit confused now - unsure which settings to change, I've uploaded 3 pictures that make up the 1 section of my motherboard used for overclocking, if you could help me by pointing up which sections to change and what settings to input, that'd be great!
FSB Frequency 370 => 400
DRAM Frequency Auto => 800Mhz
First 4 RAM timings to OCZ's specifications.
CPU Voltage 1.35625V => 1.55V
RAM Voltage AUTO => As specified bye OCZ
Test with prime95 for 15-30min and keep an eye on your temps.
Try to keep it under 75c but remember that real life usage will be lower than stress testing temps.
If it is stable after a quick run, lower the CPU Voltage bye one notch and retest.
Continue in this manor until you begin to get errors.
At this point, raise your CPU Voltage 2 settings and save the profile.
It is fun to have a maximum overclocked profile but for day to day use consider setting it at 8*400Mhz with a lower Vcore.
Still more than enough power and a lot lower temps.
Thanks outlw6669, this is working so far - at 3.6GHZ atm and a Vcore of 1.47500, been working my way down from 1.52 and its been stable on prime95 for 15mins each time - will update when the system becomes unstable
76c is high but still just acceptiable.
Remember that stress testing is putting an artificially high load on your CPU.
As such, under normal use, you should never put that much of a load on it and your temps should be lower.
Try stress testing for 8+ hours to make sure everything is 100% stable and call it a night!
That means he's going to be gaming in the mid to high 60's Centigrade, you think that's a good idea for long term use? Encoding video or anything well coded for quads, would probably push it close to 70 or so. I think your pushing it a little with those temps. Not necessarily dangerous, but in my opinion, will shorted the life of the cpu. Also consider that high voltage plays a factor in killing chips faster than normal as well, so you have that too.
No, I do not believe it is a good move for 24x7 useage.
As you say, it will shorten the life of the CPU buy a decent ammount.
As such, I recomend(ed) keeping it at 8x400 with a lower Vcore for 24x7 useage.
Looking at how much life it will take off the CPU, though.
Even if it cuts it's lifespan buy 50%, it will probably be time to upgrade before it dies.
So, if it would last 10 years, now it will only last 5 years.
Not trying to say that it is a good thing just trying to be objective about it...