i7 2600k will only work using 2 cores

[ira100]

computer has been running strong sence new abt 9 monhs
To day it blue screened and wouldnt boot

cleared bios set all to default
tryed different mem , ps,
blue screened trying to install win7 it rebooted after instllling files
finely got it to boot xp in safe mode was very unstable
got to run by selecting 2 of the 4 cores in bios
now it s running stable on 2 cores 4.7 @ 1.295 v

any ideas is mb bad or cpu

i7 2600k @ 4.7
Asus P8P67 DELUXE
8 gig cosair
cmx8gx3m2a133c9

 

[Don Karnage]

It wont even be stable with 4 cores on stock speeds and volts?

 

[Ratman6161]

computer has been running strong sence new abt 9 monhs
To day it blue screened and wouldnt boot

...
now it s running stable on 2 cores 4.7 @ 1.295 v

any ideas is mb bad or cpu

i7 2600k @ 4.7
Asus P8P67 DELUXE
8 gig cosair
cmx8gx3m2a133c9

4.7 is a pretty high overclock and 1.295 V is very low voltage for that speed. I'd do a couple of things.

First turn on all 4 cores and run everything at stock speeds and voltages.

Next, when a system has been running fine for a while and then suddenly stops - suspect heat. Check your temperatures. Shut down the system and blow/vacume out all the dust etc.

True story: way back when in the days of my AMD K63+ 450 oc'd to a massive 600 Mhz my system also started blue screening for no apparent reason. Updated drivers, did crazy amounts of trouble shooting. Tried re-installing the OS (NT 4 at the time). Nothing worked. Finally opened up the case and found it full of dust and cat hair. There was so much cat hair in the cpu fan that the fan had stopped running.

Just saying - look to the easy and obvious first

 

[Rvenger]

1. Windows XP (especially 32bit) is not fully optimized for your hardware.
2. Remove overclock and run stock
3. If running stock fan (which I hope you are not since you are OC'd) check to see if pins are properly seated and check your temps.
3. P8P67 Deluxe could have killed the CPU (seems to be somewhat of an occurrence with this board) http://forums.anandtech.com/showthread.php?t=2226974
4. Powersupply could be failing
5. Memory is faulty
6. List can go on and on...
7. We need a little more detail.

 

[Idontcare]

Welcome to the forums ira100

 

[Magic Carpet]

cpu degradation?

 

[ira100]

1. Windows XP (especially 32bit) is not fully optimized for your hardware.
2. Remove overclock and run stock
3. If running stock fan (which I hope you are not since you are OC'd) check to see if pins are properly seated and check your temps.
3. P8P67 Deluxe could have killed the CPU (seems to be somewhat of an occurrence with this board) http://forums.anandtech.com/showthread.php?t=2226974
4. Powersupply could be failing
5. Memory is faulty
6. List can go on and on...
7. We need a little more detail.

I tryed all of that it will reboot or blue screen under any load
on 4 cores