Found a weird Radeon HD 7950 with 1536 shaders and no temperature readout

[sam_86314]

While thrift shopping yesterday, I came across this guy for $35.

Upon first glance, it just looked like a normal 7900-series GPU. The sticker that the thrift store put on it said it was a Radeon HD 7950.

After sticking it into my testing system, things got a bit weird.

The first weird thing is that it only has 1536 shaders, whereas a normal HD 7950 has 1792. The other weird thing is that the temperature reports as 0C, and the fan always runs at 40%.

It has a dual BIOS switch, and the other BIOS has only 768 shaders enabled and lower clock speeds, with the fan locked at 60% instead.

Interestingly, when set to BIOS 1, it works perfectly in my dad's 2010 Mac Pro (other than the temperature readout). The boot select screen and GPU acceleration work perfectly in macOS.

Taking the card apart, some more interesting things popped up.

The sticker on the back says "MONICA" instead of the card's normal name. From what I've found, this means it's a developer sample.

It has Hynix VRAM chips.

I tried flashing a normal HD 7950 BIOS to it, but aside from breaking video output, it also didn't unlock any shaders or fix the temp readout.

Does anyone know what the deal is with this card? Is it just a normal Mac Pro version, or is it some weird (potentially rare) developer version?

I've included both BIOS files.

 

[DirtyDingusMcgee]

It's a 7870 XT. Didn't see many of them.

Scratch that. It has the memory config of an r9 280 or 8950, but the rest is like a 7870XT (and granted that all the Tahiti chips are basically the same.) I'm not really sure what you have there. i'll keep looking. interesting.

 

[sam_86314]

It's a 7870 XT. Didn't see many of them.

But it has 3GB of VRAM and the Tahiti Pro GPU rather than the Tahiti LE.

 

[DirtyDingusMcgee]

But it has 3GB of VRAM and the Tahiti Pro GPU rather than the Tahiti LE.

you are correct.

 

[LabRat 891]

AMD Radeon HD 7950 Monica BIOS 1 Specs

AMD Tahiti, 925 MHz, 1536 Cores, 96 TMUs, 32 ROPs, 3072 MB GDDR5, 1250 MHz, 384 bit

www.techpowerup.com

AMD Radeon HD 7950 Monica BIOS 2 Specs

AMD Tahiti, 800 MHz, 768 Cores, 48 TMUs, 32 ROPs, 3072 MB GDDR5, 1250 MHz, 384 bit

www.techpowerup.com

Seems like some in-between OEM card, that existed in a decent quantity.

 

[sam_86314]

AMD Radeon HD 7950 Monica BIOS 1 Specs

AMD Tahiti, 925 MHz, 1536 Cores, 96 TMUs, 32 ROPs, 3072 MB GDDR5, 1250 MHz, 384 bit

www.techpowerup.com

AMD Radeon HD 7950 Monica BIOS 2 Specs

AMD Tahiti, 800 MHz, 768 Cores, 48 TMUs, 32 ROPs, 3072 MB GDDR5, 1250 MHz, 384 bit

www.techpowerup.com

Seems like some in-between OEM card, that existed in a decent quantity.

Yeah, that was pretty much the only thing I had found about it.

 

[LabRat 891]

Yeah, that was pretty much the only thing I had found about it.

Personally, my guess: This is what happened to the silicon that couldn't make the cut for Mac/Mac Pro cards.
The 'low power' / 'mid power' vBIOS switch is intriguing, though.

Only commercial use I can think of for such, would be something like video slot/poker machines or Medical Imaging equipment. -where one unit might be passively cooled, and another actively; but, all the GPUs were bought in-lot qty.

 

[DirtyDingusMcgee]

And the card reports itself to be a 280x?

 

[LabRat 891]

And the card reports itself to be a 280x?

I'd feel confident in

A. The previous owner was also some flavor of enthusiast-tinkerer, and took advantage of the dual vBIOS. -Flashing the 'rebrand upgrade' vBIOS for otherwise the same/similar card.
B. GPU-z's having a fit because it's an odd card; and the 280X 'better fits' the ID, etc. GPU-z is reading

 

[Ruru]

And the card reports itself to be a 280x?

It's not that rare with newer drivers. My 7970 Matrix reports itself as a "7900 / 200 series".

 

[sam_86314]

I'd feel confident in

A. The previous owner was also some flavor of enthusiast-tinkerer, and took advantage of the dual vBIOS. -Flashing the 'rebrand upgrade' vBIOS for otherwise the same/similar card.
B. GPU-z's having a fit because it's an odd card; and the 280X 'better fits' the ID, etc. GPU-z is reading

I'm running the Radeon ID/NimeZ drivers, so that's why it says R9 280X. It normally reports as a 7900 series.

 

[DirtyDingusMcgee]

For 35 bucks, i'd say it is a great candidate for swapping around some bios to see what it will do.

Coming across something like that is always cool. Big style points on the find.

 

[eidairaman1]

Yeah, that was pretty much the only thing I had found about it.

States a Dev Card, so a prototype

Alternative was this

AMD FirePro D500 Specs

AMD Tahiti, 725 MHz, 1536 Cores, 96 TMUs, 32 ROPs, 3072 MB GDDR5, 1270 MHz, 384 bit

www.techpowerup.com

For 35 bucks, i'd say it is a great candidate for swapping around some bios to see what it will do.

Coming across something like that is always cool. Big style points on the find.

 

[sam_86314]

States a Dev Card, so a prototype

Alternative was this

AMD FirePro D500 Specs

AMD Tahiti, 725 MHz, 1536 Cores, 96 TMUs, 32 ROPs, 3072 MB GDDR5, 1270 MHz, 384 bit

www.techpowerup.com

Do you know of any particular BIOS I could try on it to fix the temperature readout and shader count?

 

[eidairaman1]

Do you know of any particular BIOS I could try on it to fix the temperature readout and shader count?

I don't have an answer for that 1.

Keep in mind that I believe after the HD6000 series AMD started Lasering off certain defective parts of the chips, my card is 1 gen newer and there is no unlocking it to a 290X as of shaders. Also temp reading might not even be implemented on that board until a later or pre release came about (hardware present for it). We can try to look for a bios though.

These are verified files based upon your Device ID and Sub System ID, 1002 twice is definitely an AMD Reference style for sure.

TechPowerUp

Extensive repository of graphics card BIOS image files. Our database covers submissions categorized by GPU vendor, type, and board partner variant.

www.techpowerup.com

@sam_86314

 

[Ruru]

I don't have an answer for that 1.

Keep in mind that I believe after the HD6000 series AMD started Lasering off certain defective parts of the chips, my card is 1 gen newer and there is no unlocking it to a 290X as of shaders.

Didn't some 290 cards have unlockable GPUs? Also some Fury cards had unlockable shaders.

 

[eidairaman1]

These 2 files bump the clocks up.

Powercolor HD 7950 VBIOS

3 GB GDDR5, 950 MHz GPU, 1400 MHz Memory

www.techpowerup.com

Sapphire HD 7950 VBIOS

3 GB GDDR5, 1100 MHz GPU, 1600 MHz Memory

www.techpowerup.com

Rest of the files

TechPowerUp

Extensive repository of graphics card BIOS image files. Our database covers submissions categorized by GPU vendor, type, and board partner variant.

www.techpowerup.com

Didn't some 290 cards have unlockable GPUs? Also some Fury cards had unlockable shaders.

Very very rare, i checked on mine some time ago and a tool stated it cannot be, i believe it was on ocn or ocuk.

The only other option @sam_86314 is to try a HD 7970/GHz Edition Bios or a 280/280X bios, but with this I really suggest a spi flasher so you can recover

Too bad you couldn't make this card into a 6GB model

@LabRat 891 and @damric seem to be the ones to go by for these kind of mods. I just primarily handle restoring cards to a factory working state.

 

[Caring1]

Best match I could come up with is this, but the GPU variant number on yours doesn't match anything I can find.

AMD Radeon HD 8950 OEM Specs

AMD Tahiti, 925 MHz, 1792 Cores, 112 TMUs, 32 ROPs, 3072 MB GDDR5, 1250 MHz, 384 bit

www.techpowerup.com

 

[Outback Bronze]

The first weird thing

TBH it actually more looks like a 7970, if it's made by AMD going by original HSF. It has an 8 pin + 6 pin.

Here is a pcb image of W1zzards 7950 review. It only has 2x6 pin:

 

[damric]

Barco MXRT card?