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

[LedHed]

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.

[Lvcoyote]

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.

[LedHed]

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.

[Lvcoyote]

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??

[LedHed]

Cooling:



(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.

[Lvcoyote]

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....

[Pedro Rocha]

Moved - post in the wrong section !!!

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

[R31Nismoid]

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

[Technophobe]

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