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my core i5 overclock is unstable

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New Member
Dec 23, 2009
I'm currently at 3.8Ghz, 1.200V core, and 1.195V Vtt. Prime95 failed after 6 hours, with temps reaching 81C.

Is there a way I can reach 12hour Prime95 stability without slowing the processor down or increasing max temp? I realize a better cooler than the Freezer 7 pro would do the trick, but I'm trying to save money. I'm wondering if changing the PCI-e frequency (at 100 right now) or the CPU amplitude (800) might do something.

The other voltages are 1.162 DRAM, 1.820 PLL, and 1.065 PCH. RAM is DDR3 2000, currently at 1900Mhz 9-9-9-27 (default).

Thanks for your help!


Inactive Moderator
Dec 17, 2000
Portland, OR
What MB are you using? And also post a direct link to your specific RAM showing quantity, SPD timings, and voltage.


Oct 12, 2009
5280, USA
Looks like your limited by your cooling setup at the moment. Those voltages look decent, and since increasing voltage will increase temps more your pretty much at the end of the runway in terms of overclocking flexibility.

Better case cooling + lower ambient temperatures + better heatsync & proper mounting are about your only options in terms of being able to increase vcore...and thus increasing stability.


Nov 26, 2009
I used the F7P Rev 2 before I upgraded to H50 and it never ran that high, maybe max @ 65 @ 3.6Ghz 1.25V. What is you ambient temp.?

Try resetting the cooler, it doesn't look right.


New Member
Dec 27, 2009
System Type DDR3
M/B Chipset Intel P55
CAS Latency 9-9-9-27-2N

4GB (2GB x2) /

8GB (2GB x4)
Speed DDR3-2000 (PC3 16000)
Test Voltage 1.6 Volts
Registered/Unbuffered Unbuffered
Error Checking Non-ECC
Type 240-pin DIMM
Warranty Lifetime

Essentially, you should run this at 1333 - 1688 MHz, it can be ran at 2000 MHz, but your CPU even at 4.3 GHz may not be able to fully utilize it, and Lower Timings = Faster Read / Write / Copy speed!

So Lower Timings = Better than Higher MHz!! (But not in all cases!)
The Board you have is stock 1333 though it can run 2000, I'd say you have to find a happy medium but You should always stay within the recommended timings / voltage & MHz of your RAM recommended by the manufacturer. (Especially when overclocking)

If you go above or below the timings you will most likely cause instability of your system..

1.6-1.65v is the proper voltage range for your ram, it should be running cool...
I really really need to know your current settings (all) to understand why you are have such high temps
I'm running 3.5 GHz @ <60c on a full load on a freaking Fan Cooler, so you definitely have something wrong here...


Feb 22, 2009
Check SaveMadMax's thread or Mine Pertaining to the use of Turbo Boost as an alternative to Raw Overclock speed. Looks like most Benches will turn out about equal.


Feb 22, 2009
My first suggestion would be your Core Voltage. 1.223V is fairly low. My i5 won't do higher than 3.8 w/o at least 1.39-1.42Volts. Also your Multiplier is set at 19. Set it for 20 or 21 if your motherboard allows it.