One way to undervolt R9 300 series cards by BIOS mod

[genuin]

But the memory controller load is usually over 90% if I set the frequency to be 1250 MHz. I think Etehreum uses a lot of memory access.

yes sir ,in fact Etehreum uses a lot of memory access

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[adaseb]

The best I could get was this

27.1MH/s using 170watts running at 950/1500 using 0.938V

So about ~ 6.3W/MHS.

[Heardalis]

The best I could get was this

27.1MH/s using 170watts running at 950/1500 using 0.938V

So about ~ 6.3W/MHS.

with a bios mod?
can u share the mod?

Also try it on Dual?

[sp_]

I get 26mhash eth and 500mhash sia (-dcri 40)  at around 180watt per 390( gigabyte g1). ( modded bios)

Using claymore v 5.3

[Heardalis]

I get 26mhash eth and 500mhash sia (-dcri 40)  at around 180watt per 390( gigabyte g1). ( modded bios)

Using claymore v 5.3

cool...so can u share ur mod ?

[adaseb]

I get 26mhash eth and 500mhash sia (-dcri 40)  at around 180watt per 390( gigabyte g1). ( modded bios)

Using claymore v 5.3

So if you only mined ETH without sia it would only use 140watts ?

[adaseb]

The best I could get was this

27.1MH/s using 170watts running at 950/1500 using 0.938V

So about ~ 6.3W/MHS.

with a bios mod?
can u share the mod?

Also try it on Dual?

Read the first post and try those instructions. I can't post my ROM because its only for my specific card. Use HawaiiBiosReader and edit the values manually and flash.

[sp_]

I get 26mhash eth and 500mhash sia (-dcri 40)  at around 180watt per 390( gigabyte g1). ( modded bios)

Using claymore v 5.3

So if you only mined ETH without sia it would only use 140watts ?

I think it was 160W. Don't remember. I flashed around 100 cards and only 2 have failed. Needed to reflash to default. I also have some xfx 390 cards, and get more errors with these. I think the G1 series has bether asic quality. I made 2 mods with almost the same settings.

[sp_]

I get 26mhash eth and 500mhash sia (-dcri 40)  at around 180watt per 390( gigabyte g1). ( modded bios)
Using claymore v 5.3

cool...so can u share ur mod ?

No, but it is not very dificult. Use the hawaiibios tool and try yourself.

[naum1881]

I've already got at least the same results: only 3 cards out of 100 don't want to work with a table mentioned in first post.
What can you advise me to do with those 3 cards?
 

[bobben2]

Hi Bobben 2,

thx for your detailed post. Everything is fine for our R9 390 cards in common, but we really expected some troubles in stability with only several cards out of 100+.

You've already edited bios for 380X, could you, pls., share it with us?


Thank you in advance.

Hi ,
I added links to modded BIOS files in the O.P.
Cheers.

[NewbieTreider]

Thank you for share bobben2!

I will try the 380x bios once I back home!

Again, Thank you very much!

[crazyearner]

What would be a good wattage drop can do on the cards without effecting has rate that much on sapphire r9 390 nitro card  using core voltage (mV) on mis after burn??

[Pmalek]

I have been following Bobben's first post but I dont understand this voltages on my Gigabyte 390 card...

Here is the screen

[Gigabyte 390 bios.jpg](https://postimg.org/image/brf8wjm89/)

[Q_R_V]

I have been following Bobben's first post but I dont understand this voltages on my Gigabyte 390 card...

Here is the screen

[Gigabyte 390 bios.jpg](https://postimg.org/image/brf8wjm89/)

Put Bobben's values into four "Voltage" tabs in "Limit Tables" section + into two "Voltage" tabs in "PowerPlay" section.

[uncaer9]

currently im running 2x saphire nitro  R9 390 im undervolt to -15% and overclock to 1100mz no mod bios and running perfect at 31mhs
if i mod my bios what i get ?

[Deepcleen]

currently im running 2x saphire nitro  R9 390 im undervolt to -15% and overclock to 1100mz no mod bios and running perfect at 31mhs
if i mod my bios what i get ?

For my own mod, I run the R9 390 below 1000mV, but the Core/Memory is just 975/1000 MHz, so the hash rate is just 27.4 MH/s.

[Sarspin]

currently im running 2x saphire nitro  R9 390 im undervolt to -15% and overclock to 1100mz no mod bios and running perfect at 31mhs
if i mod my bios what i get ?

For my own mod, I run the R9 390 below 1000mV, but the Core/Memory is just 975/1000 MHz, so the hash rate is just 27.4 MH/s.

You might need to mod the memory strap timing.

I heard the Eliovp has modified the Sapphire Nitro cards in the past.

[beks1]

Any bios for sapphire 380 Nitro (elpida)?

[Sarspin]

Any bios for sapphire 380 Nitro (elpida)?

You can use some kind of BIOS editor to do the mod yourself. There are many instructions on the internet.