8700k throttling under realbench at only 4.6G

facboy · 26 Nov 2017 at 01:19

hi,

just trying to get a very mild o/c going, basically MCE without the crazy voltages. i'm using a Maximus X Hero and an 8700K with 16GB of 8 Pack 3600C16. The problem I'm having is that when stress-testing RealBench the cores drop to 4.6 and HwInfo reports that the core power limit has been reached. The CPU Package Power in HwInfo also reports 95W only (or thereabouts), though it shows a max of 103W. Temps aren't a problem, max that it hits is around 60C. The VCore in HwInfo when it's running at 4.6 is also only 1.186V or thereabouts.

BIOS Settings below:

XMP
MCE disabled
Sync All Cores to 47
Adaptive Voltage 1.325V
VCCSA 1.20
VCCIO 1.15
IA AC Load Line 0.01
Ia DC Load Line 0.01
LLC 5
CPU Current Cap: 140%

Panos · 26 Nov 2017 at 08:59

Adaptive doesn't work for some boards.

gavinh87 · 26 Nov 2017 at 09:13

Try increasing cpu current capability under digi+

facboy · 26 Nov 2017 at 10:52

oh, i thought i put that in there, i already tried that

.

what do you mean Adaptive doesn't work?

voidshatter · 26 Nov 2017 at 11:08

Has the CPU been delidded? Not sure whether delidding is the standard of 8 Pack products. Lower temperature could help with throttling.

Danny75 · 26 Nov 2017 at 11:25

What happens when you try 48 all cores? Do the cores go up to 47 during Realbench or stay at 46?

gavinh87 · 26 Nov 2017 at 13:03

Try using manual voltage instead of adaptive.

abui1806 · 26 Nov 2017 at 13:05

Avx = 0?

awaybreaktoday · 26 Nov 2017 at 13:17

Try at stock settings...

facboy · 26 Nov 2017 at 14:25

It's fine at stock, but obviously only runs at 4.3 because that's how stock turbo works. It's a standard retail CPU so has not been delidded, but I don't think it's temp-related, it's in a custom loop by itself and is only running at 56 deg when it is throttled, max seen was 63.

I haven't tried 48 yet, was trying to start with plain multi-core turbo. AVX is 0.

I should say that the cores do run at 4.7, just not during realbench stress test. They also start at 4.7 during the stress test, just after a while they drop to 4.6.

[ui]ICEMAN · 26 Nov 2017 at 14:34

What happens if you leave MCE on? I read some similar posts with the Hero that did the same thing, yet wouldn’t drop speed if MCE was on.

I know it’s not what you’re after long term, but it would be useful to know if it changes things.

facboy · 26 Nov 2017 at 15:23

it seemed to be unstable just turning MCE on and keeping the above settings. as in, not even realbench, just at the desktop.

[ui]ICEMAN · 26 Nov 2017 at 19:54

Well for reference, I can't get 4.8 stable for the life of me without MCE being on. If I do anything except turn MCE on, and change Ia AC Load Line 0.01 and Ia DC Load Line 0.01, I can't get it stable.

All I've adjusted is XMP, sync all to 48x, MCE on, AC/DC = 0.01, and vcore fixed at 1.28.

facboy · 26 Nov 2017 at 23:07

so do people who are going for 5.0+ have MCE on?

[ui]ICEMAN · 26 Nov 2017 at 23:36

facboy said:
so do people who are going for 5.0+ have MCE on?

Not usually, I just haven't had enough time to really play around to figure out why I can't get it stable without it.

jasonsony735 · 27 Nov 2017 at 09:48

Is it possible to O/C Retail i7 8700k ? or do you have to delide it first

Reeve · 27 Nov 2017 at 18:28

jasonsony735 said:
Is it possible to O/C Retail i7 8700k ? or do you have to delide it first

Theres nothing stopping you overclocking with a standard 8700k. Delidding just helps the processor to maintain lower temperatures for the same speed which allows for higher max clocks. The difference isn't going to be enormous but its obviously big enough for some enthusiasts to justify paying a fair amount extra for it or risk doing it themselves.

Doogles · 27 Nov 2017 at 18:47

Have you checked the motherboard VRM's to make sure they are not overheating? With a custom loop you might not have sufficient cooling on them depending on the motherboard.

jasonsony735 · 28 Nov 2017 at 09:26

Ah ok well at idol its hitting around 35 - 40c on standard clock so I may give it ago.

facboy · 29 Nov 2017 at 22:04

as a follow up, and after looking on the ROG forums, it turned out to be the Long Duration Package Power Limit. Apparently if you enable XMP and then select No, the 'Auto' values use the default processor TDP which is 95W: https://rog.asus.com/forum/showthre...-required-ASAP&p=681302&viewfull=1#post681302 The post is in reference to the Strix motherboard but the same issue/whatever must affect the Maximus X Hero as well. It seems the only way to 'fix' the Auto values is to Reset to Defaults and then say Yes when asked. Or you could just set the values manually.

My CPU uses 95W at 4.6 on 6 cores in RealBench, I saw it peaking at 102-103 in HwInfo, so I just manually set the Long Duration Package Power Limit as I did to 105. Problem solved. Has passed 15m of RealBench at 4.7 on all cores using only 1.168V as reported by HwInfo, which seems pretty low to me! Might do a longer run to really check stability, or I may just let it throttle to 4.6 under huge loads as > 10% power increase for 100Mhz is not very efficient. Equally I may set it back to stock as it only uses 70-75W to do 6 cores at 4.3-4.4, so > 30% power increase for 300Mhz :S.