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SOLVED Motherboard can't supply CPU and RAM overclock at the same time

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ceslen

Registered
Joined
Sep 27, 2018
So after many, many hours testing for stability I have finally found my stable overclock (Thank you Earthdog and trents)
At one point I even had my vcore up into uncomfortable territory (1.42 for me) looking for stability.
In the end I discovered my issue wasn't having enough vcore but having what appears to be too much of a load (?) from the cpu overclock and the ram overclock at the same time.

I had been running the xmp oc for the ram at 3200 which was putting 1.35v to the dram. I experienced extreme temps and shut downs during my cpu overclock tests after a certain point (4.6 and beyond seemed to be the point the issues started to appear)
I decided to reset my ram oc and try undervolting it. I finally settled at 2666 with 1.2012v even though the ram I am using is G.Skill 3200. I then attempted my cpu overclock again and was able to push it much higher. Currently completely prime29.4 stable at 4.9 adaptive 1.2-1.332v with a -2avx offset with both avx on and avx off prime tests.

I have my vrm temp monitoring turned off on the motherboard because I could see what appeared to be power throttling on on intel power gadget a few minutes after I had started the prime test. When I turned off my vrm temp protection, the issue disappeared. (I do also have all my power limits maxed out). I have tightened the heatsinks on the vrms and have a 120mm fan pointed directly at them.
I checked the vrm temps (bottom of heatsink) with an ir thermometer and they appear to run around 50-60 with my 2666 1.2v, but way up around 80-90 with the 3200 1.35v which seems odd for ram that is listed as 3200 capable on the chip.
I have memtested the ram at both speeds and it passes.

I was unsure about posting here in the motherboard forum (for the vrm questions) or in the memory forum (for the ram voltage questions)
Does this sound more like a vrm limit issue or like a ram is acting up issue?
 
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trents

Senior Member
Joined
Dec 27, 2008
Sounds like your CPU has a weak IMC for some reason. Most modern Intel CPUs have no problem running 3200 mhz RAM.

But have you tried giving the IMC some extra voltage?
 
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ceslen

Registered
Joined
Sep 27, 2018
Sounds like your CPU has a weak IMC for some reason. Most modern Intel CPUs have no problem running 3200 mhz RAM.

But have you tried giving the IMC some extra voltage?

I'll fiddle with that today and see if I can get it pushed up without destabilizing the cpu oc.
Thanks trents :thup:
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
Looks like motherboard is auto adjusting some voltages too high. Usually too high SA and some PLL are bumping CPU temp. Sometimes also CPU/cache voltage is higher.
I haven't seen any CL CPU that couldn't make 4000 stable ... and I mean Celerons can make 4000-4133. It's more like a matter of motherboard/BIOS than the IMC.
 

Mandrake4565

Mr. Clean Senior Member
Joined
Jan 12, 2012
caslen, it isn't uncommon when pushing an overclock you will sometimes have to lower the memory. That said this is usually an occurrence only when really pushing to extremes. Have you tested the Ram with the Cpu at stock settings just to make sure it's stable at 3200?
 
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ceslen

Registered
Joined
Sep 27, 2018
Hey guys,
Thanks for the feedback. It seems trents and Womack sent me down the right path again. I wasn't able to find an exact imc setting in my bios, I did find that the xmp settings had adjusted the vccio & system agent voltages to auto and was sending them shooting to the moon. I re-enabled the 3200 xmp profile but this time set the vccio and sys agent voltages to 1.1. The cpu appears to still be stable at both my peak frequency and avx offset in prime, as well as having the memory running at 3200. I'm rerunning all tests stability tests now to make sure I haven't missed anything and will step those two voltages to their minimum if I can.
There doesn't seem to be very much on this board that can be left to auto without wreaking havoc on other systems. Maybe I've just been lucky in the past, or maybe I've just never really had a stable overclocked system and thought I did lol.
Regardless thank you again :salute:
 

mirzavanyaa

New Member
Joined
Nov 7, 2018
That said this is usually an occurrence only when really pushing to extremes. Have you tested the Ram with the Cpu at stock settings just to make sure it's stable at 3200?

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ceslen

Registered
Joined
Sep 27, 2018
I’ll flip back to stock settings and double check but I’ve run though all the stress test to check for failures first thing before I started the overclock. Nothing wrong with running it again real fast :)