6950 Crossfire

[TerryMathews]

I scored a good deal today on (what I thought) was a matched pair of Sapphire 6950 Dirt 3 edition cards.

I say what I thought because one will unlock to 6970 shaders and one won't. I've made sure the switch was in the right spot, and I've also flashed the original BIOS for the card that is supposed to unlock the shaders. I know that AMD started laser cutting the shaders after a while, so it seems that I got the bad luck of getting cards out of two different batches.

My question is, is it worth trading off the gimped 6950 for one that will unlock? From what I've read, at stock clocks, unlocking the shaders is about a 5% performance boost, scaling up with clocks. I've also read that the different fill rates will amplify microstuttering in crossfire - so I either need to be both locked or both unlocked.

Anyone have any constructive thoughts? I'm figuring, before shipping and Paypal fees, it'll probably cost me $20 to trade up. Figure in those additional costs, and I'm probably closer to $40 to upgrade... Seems expensive, to me.

 

[Shmee]

Hmm, I had 2 XFX 6950's, both I unlocked. Keep in mind, unlocking often means the card won't OC as well, I believe. Have you tried using Radeon bios editor to ONLY unlock shaders? You don't want to change anything else from the bios, and so when you flash you will actually be flashing each with its own bios, just with an unlocked shader count.

If it still doesn't work, it is luck of the draw with unlocking, but what would I do? I would probably either keep one unlocked and one locked, or keep both locked and see how far I could OC them then

 

[TerryMathews]

Hmm, I had 2 XFX 6950's, both I unlocked. Keep in mind, unlocking often means the card won't OC as well, I believe. Have you tried using Radeon bios editor to ONLY unlock shaders? You don't want to change anything else from the bios, and so when you flash you will actually be flashing each with its own bios, just with an unlocked shader count.

If it still doesn't work, it is luck of the draw with unlocking, but what would I do? I would probably either keep one unlocked and one locked, or keep both locked and see how far I could OC them then

I haven't modded one myself, but I pulled it from the TechPowerUp VGA BIOS archive, and it's marked that it unlocks shaders.

FWIW, I flashed the same BIOS to both cards. One reports 88 shaders, the other 96. It's not the BIOS, it's the card.

 

[jacktesterson]

Not worth it.

Keep them and Crossfire.

 

[Smoblikat]

I have 3 HD 6950's that unlocked and 1 stock HD6970. 2 of my 6950's were done with the traditional BIOS flashing method, but one used the "bubblegum" mod........look it up.

 

[TerryMathews]

I have 3 HD 6950's that unlocked and 1 stock HD6970. 2 of my 6950's were done with the traditional BIOS flashing method, but one used the "bubblegum" mod........look it up.

I'll give it a shot, but I'm pretty sure the card is flashing ok.

ETA: dumped the BIOSes out of both cards using ATIwinflash. Loaded each of them into the latest version of RBE, both report that they are modified for 6970 shader count.

I think I have a bum card. I get from everyone here that the consensus is that it's not worth trading the 6950 in for one that will unlock. No one answered the second part though, does having a mismatched shader count contribute to microstuttering? I will be curious to see if the supposed new driver set tomorrow does anything.

 

[hackerballs]

leave them locked..........you have enough with CFX to blow any game to dust..........why flash bios on the cards....risky

 

[nafees127]

agreed with hackerballs

6950 is already one powerful gpu and after CFX it is a beast setup beating very high end single gpu