All,
If you happen to have the Sapphire RX 470 card you can BIOS mod the core voltage quite easily using a hex editor as described below.
Possibly, this method can be used on other cards, too.

If you mod your BIOS it is at your own risk. I bear no responsibility.

I used HxD to undervolt core of my cards.

I found a recipe on overclock.net on Polaris Bios Editing - http://www.overclock.net/t/1604567/lightbox/post/25523158/id/2873391

Open the ROM BIOS file retrieved from your card in HxD.  Search for string FF 00 01 07 0C 00.
Locate the four bytes just preceeding the above string.   If the first two bytes = 8D 00 then the next two bytes is the VDDC.
Say you want a -75mV undervolt.  Then store the value F4 FF in the two bytes.  The actual value is FFF4 hex, which is -12 decimal.   (-12 x 6.25 = -75)
After edit your BIOS should read:   8D 00 F4 FF FF 00 01 07 0C 00
Save the file and open and save it with Polaris BIOS editor to update the checksum.
Then flash your card.  
After reboot you can verify the lowered voltage using the TPO GPU-Z sofware.
Good luck!

I certainly will, Nitro are easy

The free VBIOSes are nothing but Polaris BIOS Editor jobs a monkey could do.

XMR support has been added!

Keep in mind folks, this is a pre-release version. Currently, there is a bug with Windows where it crashes upon mining. We're able to reproduce it, but not able to find it.

I'd like to ask the community, though - what coin would you like to see next for SGMiner-GM?


I've gone ahead and added Wolf's fixed sgminer.exe to the release page, here: https://github.com/genesismining/sgminer-gm/releases/tag/5.3.0-gm

Is it possible to make this miner work with https://github.com/sammy007/open-ethereum-pool/blob/master/docs/STRATUM.md in near future?

Hacking the memory timings is safe, worse case you will get hardware errors and need to revert back.

However its near impossible to get 18MH/s with these 280x currently. Best to just dual mine with them.

The reference BIOS will not work with the Nitro+. You need a modded Nitro+ BIOS, which I have, as I did my 6 cards.

But it's not great. For some reason the Nitro+ cards will ignore VDDC set below 1v, it essentially bottoms out at 1v and I have to use MSI AB or similar to get it to go lower. Nearly all the cards will run with VDDC of 0.89v at 1125MHz core speed. Sio much power saving to have, just not via the BIOS. Not sure if it's a card or driver issue preventing the BIOS setting VDDC lower than 1v. My reference card doesn't experience the same problem.

Also, I'm finding very few of my Nitro+ will do 2200MHz on the RAM like my reference card, so for safety and stability I have RAM set to 2125MHz, this still get's it over 29mh/s per card.

I'll look to share the BIOS later if I remember.

Now added in Sapphire 390 mod claims to be 39MH+ Will be interesting to see but someone posted proof how true and stable this is would like some hardcore miners with the card to come along and test.

win 

480 4GB Elpida -29mhs

So I have decided on putting this thread together as they are many threads been created and being lost in time and hard to find. I am listing every one I can find here, from old cards, to new cards. I will be starting new first and working back in time to the older cards. I will be also providing details to what bios is for what card and version and brand etc. No doubt some of you will find this useful feel free to bookmark will save you having to bookmark a million different threads

List is being worked on so check back later

AMD R480

• 1. - RX480 (Reference) 31+Mh, Custom Rom

Credit to Eliovp for making this.

• 2. - Sapphire RX 480 Nitro+OC 8GB29+MH + downvolt

Credit to Jukebox for making this.

• 3. -

• 4. -

• 5. -

• 6. -

To be continued[/list]

I just got 6 Sapphire RX480 Nitro+ too.

So far my findings are that almost none of them will go higher than 2125~2150MHz stable on the memory.

When I push the memory too high, I will either get lots of memory errors according to HWINFO and this causes hash rates to fluctuate. Whereas sometimes it's almost like the memory bus is put in "limp mode" upon starting claymore miner. When this happens I don't tend to get memory errors but I can see that memory bus utilisation will be lower. As in, it might just sit at 50% and never go any higher.

For example, the first two cards I tested I set memory to 2250MHz like my reference card. I fired up claymore miner and while my reference card started mining at 31mh/s, the other two cards were only mining at 14mh/s and the memory bus utilisation was really low.

So I set memory speed back to 2200MHz on the two nitros and restarted the miner. Now I was mining at over 30mh/s on all three cards. But both nitros had fluctuating hashrates.

so I fired up HWINFO and found all three cards producing lots of memory errors, but especially the two nitros.

After much testing I've found that both these two nitros will only do 2125MHz without causing memory errors or entering limp mode. The reference card is quite happy at 2150MHz without producing errors. The other four nitros are all slightly different too, but generally 2125MHz seems to be the magic number on the bus. Incidentally, they'll all do 1150MHz on the core at just 900mv!

In short, if one card is giving you much lower hashrates, it's probably because it can't handle the high clock rate on the memory. I'd highly recommend using HWINFO to track memory errors and memory bus utilisation. In MSI AB, the utilisation is known as GPU FB. If your cards are not going upto 100% and sitting there most of the time then the bus is in "limp mode".

Hope this helps.

yup! You gonna gotta rich become very ))

2 sets of timings and Polaris Bios Editor don't like it )) Only going hex now ))

My sapphire Rx 470 4GB Nitro have elpida memory, and I have problem with polaris bios editor.

Any help? I can’t change strap

Strange, when I tried it did not want to connect to dwarfpool's 8080 port, only http 80 port was working.