FOLLOW-UP WITH RX 460--
I finally started putting my RX 460 cards back into use. On setting up the rig and placing 1 Sapphire 4GB Nitro RX 460 (Micron memory) in the 16X slot, I booted into ethOS v1.3.1 and followed the same steps as outlined below in my original "how-to" post. No other programs were running as I extracted, copied, pasted, and modified the BIOS; mining was disallowed.
As I opened the RX 460 BIOS in SRBPolaris, I was surprised to find a new tab in the GUI window, labelled "unlock". I clicked and unlocked the original BIOS, and saved it as 460-0U.rom". The original BIOS had been saved as "460-0.rom". I then opened the "460-0U.rom" file after saving, and went to the memory tab, clicked "Pimp My Straps", and saved this result as "460-0UP.rom".
Copying all three "*.rom"s back to the mining rig, I flashed the single RX 460 (GPU 0) with the "460-0U.rom" BIOS. Following this, I rebooted, and then allowed mining to restart. After a brief trial, with no overclocking, the card mined ETH at 11.9MH/s. This was an improvement from the 11.3MH/s with the unmodified card. Claymore v11.9 reported 16 Compute Units (CU) on the modified card, rather than 14.
I repeated the above procedure with the once-modified card, this time using the "460-0UP.rom" and rebooted. On reboot, I allowed mining to restart, and the twice-modded card began to mine ETH at 12.1MH/s. The Unlocked and Pimped strap further improved the hash rate.
I need to complete the rig; today was just a setup day. I may report power usage and overclocking results soon. --scryptr
SIMPLE "HOW-TO" POST--
After waiting for a reply, I went ahead and BIOS-modded my cards. My miners are on Linux boxes, Ubuntu based. I did not want to attach/re-attach GPUs and mod them on Windows boxes. So, this is what I did:
I ported into the Linux box with BitVise SSH client from my Win 7 X64 box. From the command line, using ATIFLASH for Linux and after hard reboot, I saved the stock BIOS of each card in the rig. Command line - "sudo atiflash -s 0 580-0.rom". This is a 4-card rig, so I repeated the step for each card, changing the number after the "-s" flag, and the number in the BIOS filename to match each time. This produced four files, each named "580-X.rom", where "X" is the number 0 through 3 and matches the GPU mining position. At this point, I copied all BIOS files to a backup directory. In the backup directory, each of the files could be re-named to include the serial number of the appropriate card.
Using BitVise SSH client, I copied the original saved BIOS files to my Win 7 X64 box. A thumb drive could also be used, but it takes more time.
Using SRBPolaris (a Windows program), I opened each BIOS file one-at-a-time, went to the second tab in the editor, and clicked on "Pimp MY Strap". I then saved the files as "580-XPIMP.rom", where "X" matched the GPU number as described above.
Using BitVise, the files were transferred back to the Linux mining box. Using ATIFLASH, each newly modded 580-XPIMP.rom was flashed on to the GPUs, one-at-a-time. Command line - "sudo atiflash -p 0 580-0PIMP.rom", where the number before the "PIMP" text matched the number after the "-p" flag and the GPU number as described above.
NO other programs were running on the mining box while saving or programming the BIOS files. After writing the BIOS mods to the cards, I rebooted. Mining started on reboot, and I noticed a 20-25% increase in XMR hashrate on my Sapphire Nitro+ rig with Samsung memory. A similar rig, with Sapphire Nitro+ cards and Hynix/Elpida memory, got a 10-15% increase in Ethereum hashrate. These are all dual-BIOS cards, and the stock BIOS is still in place on the second position. And, Linux does not require the ATIkmdag patcher, it just mines.
I am still not clear on how to unlock compute units on GTX 460 cards. Is this done with only the "Pimp my Straps" button? Please inform me before I ruin my cards. Thank you... --scryptr
NOTE: My Win 7 X64 box has nVidia drivers and a GTX 1080ti card for graphics. AMD drivers are not required while simply editing the RX Series BIOS file. There is also a Linux version of Polaris BIOS Editor (PBE). It works just fine but needs to be compiled from Git and launched with Mono. Linux PBE needs a desktop display, it is not a console tool for a headless system. My Linux mining boxes are all headless. --scryptr