Note: These directions worked for me when using the card on a Z97-based motherboard with AMD Radeon Driver version 16.9.2. As always, be wary of flashing any custom BIOS as there is always a risk of bricking your card.
On 6/19 Frys had a great sale for the HP Pavilion 560-p015hvr desktop PC. So there are now HP OEM RX 480 cards pulled from these systems on the market that are being snapped up by miners, though a quick Google yields no custom BIOS mods for mining. So I made my own that can get 31MH/s on Samsung chipped HP OEM RX 480 cards. Anyway, you probably got here by Googling “HP OEM RX 480 BIOS Mod” so I’ll cut to the chase.
Here are the specs of the single-fan HP cards I have (Again, this post is specific to Samsung memory variants; the visible overclocks got me 28MH/s on Claymore with the stock BIOS)
Using Polaris BIOS Editor, I first tried to mod the BIOS by copying the memory straps upward from 1500, but no success. Copied the memory straps upward from 1625 and it was still not quite stable. Tried the 1750 memory straps, and bingo! Make sure you are are using a driver version like 16.9.2 that plays nicely with cards that have a modded BIOS.
I am currently using this BIOS mod (stock BIOS with 1750 memory timings copied upwards) to mine Ethereum at 30.6MH/s in Claymore with an overclock to 2200 on the memory clock. A quick test of 2250 on the memory clock made it hit 31MH/s (!!!) in Claymore, but the single fan cooling and my terrible ambient temperatures (no AC, womp womp) made me settle for 30.6MH/s. Not bad for an OEM card!
(Disclaimer: I am not responsible for any bricked or otherwise damaged cards that result from people trying to replicate the above BIOS rom mods on their cards.)
TL;DR: Some HP OEM cards have Samsung memory. The cooling is a single fan, but it can handle Etherum mining fine. You can hit 28Mh/s with the stock BIOS with a simple overclock of memory to 2250mhz. Flashing a custom BIOS that moves the 1750 straps upward makes the card capable of hitting 31MH/s
P.S. If you are reading this and find a way to up the hashrate, please, please leave a comment and let me know. If you found this helpful, feel free to tip 0x44d601B0bE9E5C7B2256a149B8dCCd5B179657Ee (ETH)