Vega 64 flashed w/ LC BIOS - still broken on driver 21.1.1

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Jan 20, 2019
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Not so much hoping for a solution, mostly posting so if someone else searches for this they can see that yep the LC BIOS flash for Air cooled Vega is still broken, likely permanently.

For those not familiar with the issue, starting around the driver 19.1.2 release, people who flashed their air Vegas with the Liquid BIOS noticed low performance and stuttering. Looking at graphs in GPUz reveals that every couple seconds the card is briefly throttling down the core and memory clocks to extreme levels and the P-State LEDs on the card show that it's repeatedly dropping out of P6/P7 even under heavy load.

I've never seen a confirmation of the cause of this but my hypothesis is that in the newer driver releases AMD added some sort of additional safety feature that detects problems with the AIO factory installed on LC cards (which reports liquid temp and possibly pump status back to the card). I'm thinking that what's happening is every few seconds, the driver is polling the card for AIO status and when the AIO doesn't respond (because it doesn't exist on air cards), the driver perceives imminent thermal danger and immediately lowers the P-State to avoid overheating. But then the separate core/HBM/VRM temperature monitoring loop runs and says "hey wait, temps are safe, why are we throttling?" and returns the card to P7. A few seconds later the Liquid monitoring runs and again sees the lack of AIO data and the cycle continues indefinitely with the AIO monitoring code and thermal monitoring code arguing over whether the card is about to go thermonuclear. Not sure how to prove this without a LC V64 to experiment with alongside my AIO-converted air model but it's the best I can come up with.

Anyways. Hope this is informative to someone else who, like I, is still obsessively modding and tuning their Vega and was hoping the LC BIOS flash thing would be option again someday (it won't)
 
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