Re-Enable all Compute Units on the PS5-like BC-250 Cryptomining Card
The custom APU at the core of Sony’s PlayStation 5 hasn’t just been quietly powering these game consoles, but also made their way onto cryptomining cards around 2023 which are called the BC-250. The APUs on these boards differ from the one found in the PS5 most notably by having two out of eight CPU cores disabled, along with many compute units (CUs) of the iGPU. Now apparently it seems that you can re-enable these CUs per instructions by [duggasco] if you’re feeling adventurous.
As stated in the project’s README, BC-250 boards come with only 24 out of 40 CUs enabled, but this is not a permanent (e-fuse) thing. Instead you can write to two hardware registers during the GPU driver initialization, something which can be added to for example the Linux kernel module parameters.
Since many of these APUs likely had cores and CUs disabled due to them failing QA during PS5 APU manufacturing, there’s a good chance that some of the CUs truly are bad. Yet as we saw with the AMD Phenom II X3 with a supposedly bad fourth core back in the day, sometimes demand for the ‘defective’ part is high enough that good parts get mixed in as well.
Thus people like [Lowest Logan] decided to give it a shot, demonstrating the use of the patch with Bazzite Linux on a BC-250 system. After a reboot the system does indeed list 40 CUs as being enabled, and running Furmark shows a big boost in performance without any glitches or fire. There is of course thermal throttling, but that is due to the default cooling solution not being designed for running it at full blast.
Incidentally the real PS5 has only 36 active CUs, so this technically makes these unlocked APUs more powerful. With the water cooling solution demonstrated by [Lowest Logan] the thermal throttling is also resolved, showing that you can get a pretty nice gaming system out of these old cryptomining boards if you happen to win the silicon lottery.
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