E8500 Won't Pass IBT > 4.0ghz (Need Help)

So I have had my E8500@4.5ghz 1.45V, but I never tested it on IBT until last night. I clocked it up to 4.2ghz (525x8) 1.35V and it would only pass 80% of IBT no matter what voltages I tried. However I can run 4.0ghz @ 1.23V and IBT doesn't even get the chip up to 70C after 40 passes, so I don't understand why with all that voltage increase I can't pass IBT 100%...

My Voltage settings @4.2ghz were:

CPU: 1.35V
DDR: 2.3V
Chipset: +0.250V (1.36V)
FSB: +0.250V (1.33V)
CPU 1 GTL: 0.63VTT
CPU 2 GTL: 0.63VTT
MCH GTL: 0.59VTT
CPU PLL: 1.6V

FSB/NB Latch: 1333mhz
PCI-E Freq: 100
GPU Clock Skew: 200ps
MCH Clock Skew: 300ps
CPU Clock Driving Control: 900mV


My RAM is running at 1050mhz (1066 Rated) and my PL is at 12T

I chose my hardware for this system based around max OCing and I know this board can easily push the E8500 to 4.5ghz and beyond, but IBT doesn't like it over 4.0ghz.

Does anyone have any idea what I can try to get a stable IBT run @4.2ghz based on the settings above? Or any ideas in general will be appreciated.

So if your temps get to 70c @ 1.23v, what are the temps getting to at higher voltage..... I think the C2D's stat to throttle down at around 72.5 IIRC, or close to that.

Well when I pushed it to 1.38V it hit as high as 85C, but even when it stayed under 80C IBT still was saying 80% passed.

Also what are you talking about throttling at 72.5C? People are pushing 45nm Wolfdales to 80C all the time under IBT and they are completely fine with 100% pass.

I'm just quoting the thermal specs of that processor, if you have a EO stepping.....74.1c
http://processorfinder.intel.com/det...x?sSpec=SLB9K#

CO Stepping...... 72.4c
http://processorfinder.intel.com/det...x?sSpec=SLB9K#

It's not uncommon for you to see stability issues when the thermal spec has been reached or exceeded. What kind of cooling are you using??

Cooling:

http://i44.tinypic.com/29z5xxf.jpg

(Antec 900 + Tuniq Tower 120)



During any kind of normal load like Crysis:WH for 4 hours I never break 60C, only IBT brings out these kind of temps and I was under the impression that they are completely normal under IBT.

The only way I could get higher performance cooling is by going water, but for now I'm sticking with high end air.

Do you have EIST and C1E enabled in BIOS??? If so you can try disabling those. But I do not recommend running your CPU in the 80c range for any period of time....

Moved - post in the wrong section !!!

Please read this - http://www.xtremesystems.org/forums/...d.php?t=219716

:rolleyes:

Those kinda temps you only see on unlapped CPU's. Mine was above 70 until i lapped it (E8400 @ 4.3ghz), then once i did it dropped nearly 10-12 degrees as the plate is FAR from even. I was shocked at how uneven it was to be honest and fully explains my crazy temp :)

My bet is that someone is talking Tcase and the other person is talking Tjunction temperatures here...