Question Weird issues with AMD FM2 APUs and mainboards


Jan 13, 2008
Hi all,
I'll try to be quick and clear about this weird issues I'm having.

It all started with my mother in law system I put together years ago, based on an AsRock FM2A68M-HD+ and a A6-7400K APU.
It would suddenly have serious video issues, to the point of being unusable: BSODs, display going blank, system freezing, etc.
Troubleshooting a bit, I narrowed it down to the APU failing and just replaced the whole platform with a newer Athlon 3000G / B450 combo.

I got hold of another APU, just to see if I could salvage some of the parts: with an A4 5300 on that same AsRock motherboard and the same ram, all went smoothly and I had no issues at all. I went as far as running Furmark for 2 hours straight and had 0 problems.
Great, I thought, I'm putting the A6 aside 'cause it's definitely defective.

Then I got a used, guaranteed 100% working A8-7600 and was planning to do a build based around that one, as it's still a very capable chip and the A4 is way too weak.
But no, still having problems: with the A8 I get no video signal at all, via DVI, as well VGA. And the weird thing is that sometimes it does work but most of the times the system can't even get to POST.

I had another FM2+ board laying around (a Biostar A6MD Pro 6.0) : with that board, the A8 works perfectly.
Both mainboards have the latest BIOS installed and I used 4 different sticks of ram in every possible combination.
Clearing CMOS and removing the battery seems to do nothing.
Eveything is powered by a surely working Thermaltake Hamburg 80+ 530W power supply, which should be abundantly adequate for FM2 APUs (I used it for years to power my main Ryzen 5 + RX580 rig).
All of the parts have been tested in and out of a case and the 12V CPU plug is correctly inserted, as is the 24 pin connector.
Unfortunately I don't have a spare graphics card to test.

I guess it's fair to say that the video outputs on the AsRock board are working fine, as with the A4 I had no issues.
It should be also fair to say that the A8 is working fine, as on the Biostar board it has no issues.

Still, I'm in this weird place where the AsRock works with the A4 but not with the A8, and the A8 works with the Biostar but not with the AsRock!
WTH ?!

Do any of you have some suggestions?
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I also own an ASRock FM2 board, with an A10-6800K, the thing you speak of is not abnormal, more likely one of two things;
1| you lack the right BISO version for your motherboard, that's where you check and see if you have any BIOS updates pending
2| Your VRM's on the motherboard have called it quits and can't deliver more power to the higher end APU's which would explain the issue with the higher spec APU's not working.

In my instance, as time progresses I need to dial down the voltage and the clocks for the APU, to be point I'm no longer at A1-6800K specs, below it actually. If it weren't for the pandemic, I'd have migrated platforms.

FYI, that Thermaltake PSU is more of an expensive paperweight, you should replace it for a reliably built unit, asap!


Jan 13, 2008
hmm... BIOSes.
According to AsRock's website there are only two versions:

version 5.20:
  1. Update CPU/APU micro code.
  2. Improve system compatibility with Carrizo CPU
version 2.10:
Update APU AGEGA code for Carrizo support.

None of the APUs I've been using are Carrizo based, the A8-7600 is a Kaveri chip.
What if I downgraded to version 2.10?