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Hitting the wall at 4.8G AVX, should I try harder?

Joined
Apr 18, 2019
Messages
16
Motherboard
Gigabyte Z390m Gaming
CPU
i5-9600K
Graphics
RX 570
Mac
MacBook Air, MacBook Pro
Mobile Phone
iOS
This is my build: https://www.tonymacx86.com/threads/success-gigabyte-z390m-gaming-i5-9600k-asus-rx570-8gb-mojave.277462/

In short: 9600k+ Gigabyte Z390M + 120mm AIO cooler with Noctua fan

I don't game much and the performance I really care about is video editing. Here's my OC situation:

- all core 4.8G ran Handbrake overnight without an issue: 82 degree/120W drawn/all else BIOS settings (voltage, offsets) auto/actual voltage shown in BIOS ~1.30V/AVX Offset auto but I learned that MacOS ignores that anyway
- 4.9G and leave all else auto in BIOS - MacOS will crash 90% of the time at the end of a Handbrake task or DaVinci export, no obvious temperature build up before the crash
- at 4.9G increase voltage to 1.34V MacOS appears to crash even earlier during exports

Should I just be happy about the 4.8G and not try to push harder? I guess under AVX that's reasonable however I want to understand the constraint here so I know what to upgrade in the future:
- temp? I know 120mm AIO is not sexy but mine crashes without a clear sign of temp build up. At 4.8G Prime95 can run for several minutes at 95C before I quit it manually without crashing. So I don't think temp is the issue.
- voltage? should I try to hit it harder?
- power drawn? In Prime95 it can easily draw 150W without crashing. But in Handbrake it will crash at 120W.
- incorrect Intel Power Gadget reading? That's the one I used for CPU power and temperature reading. Please let me know if there's a better tool to use (including reading voltage). I have iStat Menus but it doesn't provide per core temp reading for my motherboard. MacFanControl doesn't either.

Thank you!
 

pastrychef

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Asus ROG Strix Z370-G Gaming (Wi-Fi AC)
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Try overclocking with XMP disabled so that you know that RAM is not the limiting factor.
 
Joined
Apr 18, 2019
Messages
16
Motherboard
Gigabyte Z390m Gaming
CPU
i5-9600K
Graphics
RX 570
Mac
MacBook Air, MacBook Pro
Mobile Phone
iOS
Try overclocking with XMP disabled so that you know that RAM is not the limiting factor.
Unfortunately at 4.9 without XMP the issue persists. Thanks for helping!

I went on and tried numerous combinations of CPU Vcore, dynamic Vcore and Vcore Loadline calibration settings, some yielding 4% jump in R20 however none maintained cooler than 95 before finishing my Handbrake test so I quit manually on them.
I'm guessing to OC further with heavy AVX task I need to update cooling to allow it to draw more than 140W (~30 per core) consistently. Not sure how to prove this theory tho.
 

pastrychef

Moderator
Joined
May 29, 2013
Messages
11,273
Motherboard
Asus ROG Strix Z370-G Gaming (Wi-Fi AC)
CPU
i9-9900K OC'd @ 5.0GHz
Graphics
Radeon VII
Mac
MacBook, Mac Pro
Classic Mac
iBook, Power Mac, PowerBook
Mobile Phone
iOS
Unfortunately at 4.9 without XMP the issue persists. Thanks for helping!

I went on and tried numerous combinations of CPU Vcore, dynamic Vcore and Vcore Loadline calibration settings, some yielding 4% jump in R20 however none maintained cooler than 95 before finishing my Handbrake test so I quit manually on them.
I'm guessing to OC further with heavy AVX task I need to update cooling to allow it to draw more than 140W (~30 per core) consistently. Not sure how to prove this theory tho.
Your cooler might indeed be a limiting factor. 95C is a bit warm but it's still within the TJMax of 100C...

Another thing to watch is VRM temperatures. Make sure there's at least some airflow around the VRM heatsinks.

I also have a Z390 M and I found the motherboard to be excellent for overclocking. Although I did not keep the setting, I did manage to boot with my i9-9900K at 5.2GHz @ 1.35v. I backed it down to 5.0GHz @ 1.255v for 24/7 use. This is with air cooling on a CPU I delidded myself.
 
Joined
Apr 18, 2019
Messages
16
Motherboard
Gigabyte Z390m Gaming
CPU
i5-9600K
Graphics
RX 570
Mac
MacBook Air, MacBook Pro
Mobile Phone
iOS
Your cooler might indeed be a limiting factor. 95C is a bit warm but it's still within the TJMax of 100C...

Another thing to watch is VRM temperatures. Make sure there's at least some airflow around the VRM heatsinks.

I also have a Z390 M and I found the motherboard to be excellent for overclocking. Although I did not keep the setting, I did manage to boot with my i9-9900K at 5.2GHz @ 1.35v. I backed it down to 5.0GHz @ 1.255v for 24/7 use. This is with air cooling on a CPU I delidded myself.
I did some more tests over the weekend and today and here are some observations:
  • Despite significant Cinebench R20 score difference, running a sample H.264 to H.265 handbrake test did not yield much gain OC from 4.5G to 4.8G (47m to 44.5m) and the temp difference is 10 degrees Celsius. For overnight tasks I might just use 4.5 for the peace of mind that my AIO isn't boiling inside (is that possible?) or leak under stress
  • I redistributed the case fans, tried open chassis and even using an external fan blowing into the AIO intake/VRM heatsink. With external fan CPU is 3 degrees cooler. I might reposition the fans again just to give the VRM slightly better airflow
  • I've already exchanged the AIO fan with a Noctua and I'm reading push and pull will not yield much compared to push or pull. I guess that's about the capacity for a 120mm AIO (130W?)
 

pastrychef

Moderator
Joined
May 29, 2013
Messages
11,273
Motherboard
Asus ROG Strix Z370-G Gaming (Wi-Fi AC)
CPU
i9-9900K OC'd @ 5.0GHz
Graphics
Radeon VII
Mac
MacBook, Mac Pro
Classic Mac
iBook, Power Mac, PowerBook
Mobile Phone
iOS
I did some more tests over the weekend and today and here are some observations:
  • Despite significant Cinebench R20 score difference, running a sample H.264 to H.265 handbrake test did not yield much gain OC from 4.5G to 4.8G (47m to 44.5m) and the temp difference is 10 degrees Celsius. For overnight tasks I might just use 4.5 for the peace of mind that my AIO isn't boiling inside (is that possible?) or leak under stress
  • I redistributed the case fans, tried open chassis and even using an external fan blowing into the AIO intake/VRM heatsink. With external fan CPU is 3 degrees cooler. I might reposition the fans again just to give the VRM slightly better airflow
  • I've already exchanged the AIO fan with a Noctua and I'm reading push and pull will not yield much compared to push or pull. I guess that's about the capacity for a 120mm AIO (130W?)
Get a Noctua.

 
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