EIST & moderate OCing ...

NoobyDoo

Senior member
Nov 13, 2006
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What are the implications of enabling EIST & TM1/TM2 with a mildly/moderately overclocked C2D based system. Asking because I came across this in the TechReport Forums :
* Will disabling of VT, EIST, TM(2), PCHI etc help my OC?
No, specially disabling of TM(2) and EIST is dumb. Most people have seen that people on xtremesystems.org does this. Their purpose is however, alot different than for people here. They disable EIST and TM1/TM2 so the CPU wont throttle even if overheating.
 

myocardia

Diamond Member
Jun 21, 2003
9,291
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If only the guy that wrote that post knew what he was talking about. EIST is Intel's answer to AMD's Cool n Quiet. It reduces the processor's speed, while reducing it's voltage. You can't overclock a C2D very far with it enabled, period. The reason is because your FSB will remain high, because EIST (and CnQ) only reduces the processor's multiplier, not the FSB. That means that it'd be running at a much higher frequency than Intel intended, when the EIST kicked in, and every time it did, you'd have to hard reboot.
 

Conky

Lifer
May 9, 2001
10,709
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Originally posted by: myocardia
If only the guy that wrote that post knew what he was talking about. EIST is Intel's answer to AMD's Cool n Quiet. It reduces the processor's speed, while reducing it's voltage. You can't overclock a C2D very far with it enabled, period. The reason is because your FSB will remain high, because EIST (and CnQ) only reduces the processor's multiplier, not the FSB. That means that it'd be running at a much higher frequency than Intel intended, when the EIST kicked in, and every time it did, you'd have to hard reboot.
:thumbsup:

 

Accord99

Platinum Member
Jul 2, 2001
2,259
172
106
Originally posted by: NoobyDoo
Thanks.

So, basically, you can't OC and have EIST enabled.
It depends on what your down-clocked speed is. I have a E6600 running at 3.24GHz, with EIST it drops to 2.16GHz with no problems. Some motherboards, like the P5B series, will disable the voltage reduction part of EIST as well so it won't accidentally drop to a voltage that's not high enough for the idle clock speed.