I am relatively new to mining and for the moment I only have one GPU to experiment with and that is Rx 480 sapphire nitro+ OC.
After reading lots of forums and after lots of tries, I've come to understand how to mod my bios, flash it,unlock 8gb on my card,timestrap memories.
I will make this both a guide for newcomers explaining every step to make and a discussion on the settings I've come to so far since I'd be happy to know if they are safe or efficient.GUIDE
First i'd like to mention that Rx 480 sapphire nitro has a dual bios with a switch to "silent" bios mode near the led button . The position closer to the HDMI ports is for the silent bios. So if you accidently break it you still have a chance to revert the mistake.What you need
Polaris bios editor (PBE) http://www.overclock.net/t/1604567/polaris-bios-editing-rx480-rx470-rx460
Ati flash 2.74 https://www.techpowerup.com/downloads/2728/atiflash-2-74
Amd catalyst center version 16.9 or 16.11 other versions need to be patched to work with modded bioses as they check for the bios signature and will deactivate the card http://www.sapphiretech.com/download.asp?lang=eng
How to do it
From what I read every Rx 480 sapphire nitro 4gb is in fact 8gb, but let's say that information is false, if you see this black sticker on your box it's safe to say it has in fact 8 gb.
To unlock the 8gb all you have to do is install ati flash
, open it as administrator, save your current bioses
( you will need them later, you can change the position of the bios switch even when the PC is working)
Now that you have the original bioses saved make sure you do not lose it as only with them (or with modded versions of them your GPU) will work, so in order to test my bios or one from the internet you have to copy in PBE every setting to your own bios file.Open PBE
and modify the memory size
from 4096 to 8192.
I'm sorry but I currently do not know if you have to modify the density as well, so I'll say leave it as it is.
Now save it and flash it with ATI Flash on your "silent" bios. If you break it
, you have to switch the bios, boot in windows, switch the bios on the broken one, start ATI Flash, and flash a good copy of bios.
That was unlocking the 8gb. I do not promise you will have greater hashrates or you will notice any improvement at all. For me it was the opposite, I noticed a decrease in my hashrates and in performance overall. And here comes timestrapping.Timestrapping
in short is modifing the times of the ram cycles. At lower frequencies there is a lower time for the cycle and at higher frequencies there is a higher time for a cycle. In PBE you can copy the times from lower frequencies to higher frequencies so you have tighter times between cycles. From what I read some copy the timing from 1600 mhz to those above. For me personally that didn't work so great.
I hope I was clear and this helps anyone. Now let's talk about settings.SETTINGS
As I am part gamer too and as I do not have the best power supply yet my safe settings are 1225/2150 for 30MH. If I am running any game while mining I notice small framedrops from time to time while I get 26-28MH.
For mining only I can push the limit to 1225/2200 where I get 31MH.
I mention that the bios I use is still under testing. For now it is the best I have. I have tested other bioses from this forum and not all of them work for me(the console reported 30 MH but after hours of mining the shares found were the same as if i had 16-20 MH) but they have inspired and helped me. The bios that helped me the most was v4 from Jukebox, you can find it here https://forum.ethereum.org/discussion/9650/sapphire-rx-480-nitro-oc-8gb-11260-01-20g-modded-bios-29-mh-downvolt/p5
Density of memory is the original one 0x53.
I have timestrapped all the frequencies.
Downvolted to 900.
The GPU runs on 85W.