Question CPU throttling for no apparent reason

Apr 8, 2020
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I overclocked my FX-8300 to 4.2GHz;Turbo core disabled(obviously) , C6 state disabled, Cool & Quiet disabled

I stressed the CPU with Intel Burn Test and it was perfectly stable, both CPU and MoBo temps were well within limit, but i noticed when the CPU usage goes to 100% on all cores it throttled all the way down to 1.4GHz, but only for a few seconds...

Then i ran Cinebench R15 and noticed that my score was barely 20 more than on stock settings.

Is all of this normal? Or is my CPU throttling it's performance for some reason and should i have problems playing games? (i heard that R15 and burn test push the CPU far beyond any realistic stress)

Thank you for your answers!
 
I overclocked my FX-8300 to 4.2GHz;Turbo core disabled(obviously) , C6 state disabled, Cool & Quiet disabled

I stressed the CPU with Intel Burn Test and it was perfectly stable, both CPU and MoBo temps were well within limit, but i noticed when the CPU usage goes to 100% on all cores it throttled all the way down to 1.4GHz, but only for a few seconds...

Then i ran Cinebench R15 and noticed that my score was barely 20 more than on stock settings.

Is all of this normal? Or is my CPU throttling it's performance for some reason and should i have problems playing games? (i heard that R15 and burn test push the CPU far beyond any realistic stress)

Thank you for your answers!
I had similar issues with an FX 8320 system a few years ago. The issue is likely the motherboard - if the motherboard VRM's (voltage regulators) aren't up to the task they can overheat and the motherboard will trigger the cpu to drop clocks to compensate.

What motherboard do you have? Motherboards based on the 970 chipset (like my old board) are notorious for throttling the cpu when overclocked.
 

katulen

Prominent
Apr 22, 2019
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You might be hitting power limits?
Use HWinfo64 to check.

I had same issue with my system.

If you do, max out short & long power duration limits.
 
Apr 8, 2020
38
3
35
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I had similar issues with an FX 8320 system a few years ago. The issue is likely the motherboard - if the motherboard VRM's (voltage regulators) aren't up to the task they can overheat and the motherboard will trigger the cpu to drop clocks to compensate.

What motherboard do you have? Motherboards based on the 970 chipset (like my old board) are notorious for throttling the cpu when overclocked.
Thank you for answering, when I think of it, that's probably the case. My motherboard is a s*itty m5a78l-m/usb3 with 4+1 VRMs and no heatsinks on them... Do you by any chance know what is the max OC frequency (if any) can i get out of this board? Thanks again!
 
Thank you for answering, when I think of it, that's probably the case. My motherboard is a s*itty m5a78l-m/usb3 with 4+1 VRMs and no heatsinks on them... Do you by any chance know what is the max OC frequency (if any) can i get out of this board? Thanks again!
Well looking at the board it does (at least according to Asus) support up to 140w cpu so should handle any of the FX cpu's at stock (aside from the 9000 series). As for what kind of OC you can get - it's really a case of trial and error. I would start at stock settings and make sure the frequency is 100% stable at that first in those tests. Then try increasing frequency in 100mhz increments and retest.

It's also worth looking at the cpu voltages - you might get a bit more out of the cpu if you can drop the core voltage down a bit (this is called under-volting) as it will take pressure of the VRM. The issue is if you undervolt too far you will run into stability issues like blue screens or the system just hanging. I remember on my 8320 I kept the speed at stock but managed to drop the core voltage quite a bit (I think I could run it stable with a -0.2v offset on the core which really improved temps and power use). You may find you can drop the core voltage a little (something like - 0.05 or -0.1V) and still get a bit more frequency out of the chip.

The other thing that can help is improving cooling for both the cpu and vrm - the cpu uses less power the cooler it is, which in turn gives you a bit extra headroom. Improving airflow over the VRM's can also help as they are more efficient at lower temps.
 
Apr 8, 2020
38
3
35
1
Well looking at the board it does (at least according to Asus) support up to 140w cpu so should handle any of the FX cpu's at stock (aside from the 9000 series). As for what kind of OC you can get - it's really a case of trial and error. I would start at stock settings and make sure the frequency is 100% stable at that first in those tests. Then try increasing frequency in 100mhz increments and retest.

It's also worth looking at the cpu voltages - you might get a bit more out of the cpu if you can drop the core voltage down a bit (this is called under-volting) as it will take pressure of the VRM. The issue is if you undervolt too far you will run into stability issues like blue screens or the system just hanging. I remember on my 8320 I kept the speed at stock but managed to drop the core voltage quite a bit (I think I could run it stable with a -0.2v offset on the core which really improved temps and power use). You may find you can drop the core voltage a little (something like - 0.05 or -0.1V) and still get a bit more frequency out of the chip.

The other thing that can help is improving cooling for both the cpu and vrm - the cpu uses less power the cooler it is, which in turn gives you a bit extra headroom. Improving airflow over the VRM's can also help as they are more efficient at lower temps.
Yeah I vas thinking about either undervolting or better cooling solutions. My cpu cooler is a pretty decent 180W TDP one but i am probably going to need to put some sort of a heatsink over the VRMs
 
Yeah I vas thinking about either undervolting or better cooling solutions. My cpu cooler is a pretty decent 180W TDP one but i am probably going to need to put some sort of a heatsink over the VRMs
I had a 6300 on an equally paltry motherboard and had similar problems with it overclocked above 4.4 Ghz.

Get a kit of MOSFET heatsinks and glue them on...or use thermal double sided tape. Also position a fan blowing on the VRM area to cool it. Doing that helped mine a lot but it still did it when pushed hard, but really only in stress tests.
 
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