ASUS M5A78ML is slower after putting WC

Hello

I have issue that CPU started to throttle between 3.1GHz and 1.4GHz after installing watercooling (CPU temp 29C at 3.1GHz). There was no such issue on box air cooling previously (62C). I suspect my mainboard is just 3-4 phase buck converter, and with very few phases and no air flow after installing water block, psu overheats and asus throttles CPU to protect mosfets from overheating. Any idea?

AMD fx 8120
asus m5a78ml
cooler: coolermaster Nepton 280L (previously box AC was getting 3.1GHz constant easily despite 6200rpm)
Task: Adobe Premiere Cs6, exporting 32h h264, all cores 100% for 32hours, exporting on AC 40% faster then on LC.

I don't think that board is meant to overclock heavy due to 4 phase. Try adding a fan towards the VRMs/mosfets power delivery area (left of the cpu socket) and NB sink. Hopefully that'll help some.

that will help, but in the short term that board will fail.

caddi daddi said:

that will help, but in the short term that board will fail.

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Yup, I concur.

Nebulous said:

I don't think that board is meant to overclock heavy due to 4 phase. Try adding a fan towards the VRMs/mosfets power delivery area (left of the cpu socket) and NB sink. Hopefully that'll help some.

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caddi daddi said:

that will help, but in the short term that board will fail.

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I highlighted the likely culprit. When adding a AIO water heatsink you removed the air flowing over the VRM area, from the downward drafting air heatsink. Due to your board having no heatsinks on the VRM and only a 3+1 Power phase section, the board is struggling to provide the Fx 8xxx with power and likely overheating. The throttling, is the board trying to save it's own life.

I also agree with Caddi adding fans will help, but you will be much better off running that processor on something like this

Thank you. Actually this cpu is not overclocked, 3.1GHz is its stock speed. Do you know some motherboard very similar to my asus, where Adobe Premiere cd6 and win 7 64bit will not be exposed to "cultural shock" after change of mobo? Same chipset, audio usb peripheral ICs but just more phases on power supply.

Your motherboard is only rated for 95W cpus. You have a 125W stock CPU installed. I personally owned that board and its notorious for CPU throttling. Adding a fan to the VRM will help slightly, but wont fix the issue. Point blank that board is not intended to run a high end CPU whether overclocked or not.

MadeInBolivia said:

Thank you. Actually this cpu is not overclocked, 3.1GHz is its stock speed. Do you know some motherboard very similar to my asus, where Adobe Premiere cd6 and win 7 64bit will not be exposed to "cultural shock" after change of mobo? Same chipset, audio usb peripheral ICs but just more phases on power supply.

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There is no ASUS board with the same chipset "AMD 760" which you have that would be recommended to run that Cpu. If you stick with ASUS you may be able to run either a 970/990X or 990Fx chipset but only trying will tell the tale of the tape. You may have to do a clean Os install but it may be worth a shot. These two boards are the least expensive ASUS boards I would try running a Fx 8xxx chip on. Both have a 6+2 Vrm section with heatsinks. I own and use the M5A99X evo and it's a really good board for a stock Fx 8xxx to a mild Oc of about 4.5 Ghz all depending on the chip.
Asus M5A97 R 2.0
Asus M5A99X Evo

Thank you for replies
@ssjwizard - this board is 140W: https://www.asus.com/uk/Motherboards/M5A78LMUSB3/specifications/

It runs 8120 at 3.1(stock)+turbo 8cores 100% loaded x264 through 44 hours without throttling on air (even 3.9 is fine but cooler gets 7000rpm), thats why i am extremly surprized about throttling on water at stock.

I believe non lm version was just 95W.

@Mandrake - how likely it is mobos which you recomend will not throttle when wc?

@all - can you as well be so kind to take a look on my other post on ram spèed please? Thank you.

MadeInBolivia said:

Thank you for replies
@ssjwizard - this board is 140W: https://www.asus.com/uk/Motherboards/M5A78LMUSB3/specifications/

It runs 8120 at 3.1(stock)+turbo 8cores 100% loaded x264 through 44 hours without throttling on air (even 3.9 is fine but cooler gets 7000rpm), thats why i am extremly surprized about throttling on water at stock.

I believe non lm version was just 95W.

@mandrake - how likely it is mobos which you recomend will not throttle when wc?

@all - can you as well be so kind to take a look on my other post on ram spèed please? Thank you.

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Just to re-iterate. The reason why it's throttling now is because when you removed the Air heatsink you also removed the air flowing over the VRM section. Which is now throttling because that section is getting too hot. If you put fans on that section it will likely stop throttling. Previously when I looked up your board I thought it was a 3+1 Vrm section board. The board you linked is a 4+1 Vrm section, which is a bit better. You can try just adding fans or at least heatsinks to the VRM section and run it like that. Just a precaution, these boards with under powered VRM sections struggle with these chips. If you can keep them cool it should be ok, but they could let go and take other components with it.

As far as the boards I mentioned, I cannot speak for the M5A97, I have never owned one nor do I recall one coming through here running a Fx 8xxx Cpu. As far as the M5A99X Evo it's a really good board. I've had mine for about 3 years now. For running a Fx 8xxx stock to a mild Oc it will suit you just fine. I have not experienced any throttling at all with my Fx 8350 on it up to about 4.5 Ghz. Above that the 6+2 power phase section can't keep up with the demands of the chip.

I will also look at your other post.

MadeInBolivia said:

Thank you for replies
@ssjwizard - this board is 140W: https://www.asus.com/uk/Motherboards/M5A78LMUSB3/specifications/

It runs 8120 at 3.1(stock)+turbo 8cores 100% loaded x264 through 44 hours without throttling on air (even 3.9 is fine but cooler gets 7000rpm), thats why i am extremly surprized about throttling on water at stock.

I believe non lm version was just 95W.

@mandrake - how likely it is mobos which you recomend will not throttle when wc?

@all - can you as well be so kind to take a look on my other post on ram spèed please? Thank you.

Click to expand...

Those other boards are much beefier and won't throttle. As Mandrake said the old fan cooler had residual airflow that helped cool components on the motherboard. You lose that with the AIO cooler which imho of dubious value.