Question on a CPU's stablity

newbie1337

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Hey community

My current specs are:
Cpu:i7 3770k
ram:kingston hyperx beast @ 2400mhz
mobo: asrock extreme 4 z77
Cpu cooler:corsair h60 (push pull with 2 corsair sp120's)

I'm currently trying to overclock my cpu past 4.3 ghz which i have ran for 2 weeks completely stable. But everytime i stress test with prime95 blend test after about 5 mins threads would start to crash and get errors showing the overclock wasn't stable but windows would never crash. i tried the small fft's test as it doesn't test ram as much and I've been running it for an hour now cpu 100% load hottest core 65c. Is this stable ?
 
Solution


Keep it at 2400mhz you got a lot of head room temperature wise, increase the VCCIO voltage (your integrated memory controllers voltage) should be a a fixed 1.1 - 1.2 for 2400 mhz, and set your dimm voltage manually to fixed 1.65 to prevent it from spiking. if you want lower temps you want to make sure you have more exhaust fans than intake in the upper half of your case for the best temperatures or at least exhaust equal to intake...

newbie1337

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Prime 95 never actually crashed just threads like it would still be stressing 6 threads but 2 wouldn't be being stressed at all basically 2 cores where running at 100% and 2 at 50%. The only test they crash in is the blend test
 

atomicWAR

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still if blend test is crashing its not stable. i like using intel burn test...it uses prime 95 but is designed to super heat the cpu's every square nanometer to ensure its stable. run it on maxiumum for 10 to 15 runs. if you don't crash, in my experience nothing will crash you.
 

newbie1337

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I was running @ 2400mhz on ram as it was on xmp profiles. I have had a suspicion that it was my ram effecting my overclock so set the ram to auto frequency (1333mhz) and my cpu was completely stable at 4.4ghz using intel burn test im happy with this however what speed should i try setting my ram too ?
 

hdeezie80

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Keep it at 2400mhz you got a lot of head room temperature wise, increase the VCCIO voltage (your integrated memory controllers voltage) should be a a fixed 1.1 - 1.2 for 2400 mhz, and set your dimm voltage manually to fixed 1.65 to prevent it from spiking. if you want lower temps you want to make sure you have more exhaust fans than intake in the upper half of your case for the best temperatures or at least exhaust equal to intake otherwise you get a build up of hot air, have a fan pointed towards the memory as well. Temps will be OK into the high 70's and mid 80's if your checking after an hour of prime. All the ivy bridge chips I've got my hands on seem to be able to OC to around 4.4 - 4.6 on air or closed loop coolers pretty easily before you start having problems with temperature.

 
Solution

hdeezie80

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It really only makes a difference when your going for high cpu overclocks over 5 GHz though where small decreases in temperature can help out, anything in the mid 4 GHz range isn't worth lowering the ram frequency, temperature increase is about 1-3 C in my experience after raising VCCIO/IMC voltage.
 

atomicWAR

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is that wise...sandy/ivy bridge should not go over 1.5v (or 1.575 if you includes intels 5% variation) or you risk damaging your cpu. the vicco is within spec though.

that said i have heard of peeps running that high but others get nervous at stop at 1.58
 

newbie1337

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I set the VTT (VCCIO) voltage to 1.15v @2133 and dimm voltage to 1.6v and it ran completely stable at 4.4ghz. Thanks :)
 

hdeezie80

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1.8v is the absolute max for dimm voltage, but safe voltage really depends on the quality of the motherboard/ram/IMC. 1.65V is pretty safe especially with dims rated for speeds like 2400 since they generally won't draw as much current as slower rated dimms running at the same speed plus better dimms are generally designed to handle more power without degrading. Its better to base your max "safe" voltage off of temperature, the reason being that current is what actually damages electronics and causes them to heat up, voltage is just the potential to develop current so you cant really judge if its ok to run your dimms at a certain voltage only off the value you set for it. Point being that if your temps are safe and you are not above max specs for voltages than its usually a good indication that your machine is healthy.
 

atomicWAR

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i had heard 1.8 to 1.575 so i wanted to check and make sure.
 

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