6950 BIOS switch

[Mr. Pedantic]

I just bought a Sapphire Dirt 3 edition 6950 2GB. I haven't installed it yet, but I have a small question.




See, the BIOS switch (I think it's a BIOS switch anyway) doesn't look quite like the ones on the reference cards. This is a picture of my card, by the way:

This is the area around the Crossfire connector:

And zoomed in a bit more...

See how there's a switch?


It's set back from the edge, under the heatsink cover, so the only way to move it is with a knife or something.


I just want to be assured by the opinion of people more knowledgeable than I am; without ever having put it in my computer, I think this is a BIOS switch. Do you guys think it is a BIOS switch also? If so, which position is 1 and which is 2? Or does it not matter?

 

[dennilfloss]

What's the length of your card?

 

[Mr. Pedantic]

PCB is just over 9 inches
In total it's about 10.25 inches

 

[NTAC]

This is the switch: http://s726.photobucket.com/albums/...6950 unlock/?action=view&current=IMG_1913.jpg

And I think you move it AWAY from the Crossfire connector to enable the shaders.

That was taken from this guide: http://forums.guru3d.com/showthread.php?t=350307

The switch unlocks the shaders, so you don't need to flash the bios or anything like that to get that accomplished.

IF you want to clock the card like a 6970 then you can flash or just crank it up with TRIXX. That's my understanding of the whole thing.

 

[Mr. Pedantic]

Ok, the 6950 was all stable at stock so I flipped the switch.

On startup, GPU-z shows 1536 shaders enabled. However, performance isn't actually any better than with 1408.

Furmark at 1920x1080, 8xAA still shows 37fps (6950 stock was 37) and 3DMark03 scores 80,005 (6950 stock was 80,047). These are all at stock clocks - 800/1250.


Also, Furmark still reports it as a 6950 series, and so does GPU-z. Is this normal?


Is there something else that I need to do?

 

[3DVagabond]

Ok, the 6950 was all stable at stock so I flipped the switch.

On startup, GPU-z shows 1536 shaders enabled. However, performance isn't actually any better than with 1408.

Furmark at 1920x1080, 8xAA still shows 37fps (6950 stock was 37) and 3DMark03 scores 80,005 (6950 stock was 80,047). These are all at stock clocks - 800/1250.


Also, Furmark still reports it as a 6950 series, and so does GPU-z. Is this normal?


Is there something else that I need to do?

Go into CCC and set the power control to +20. The card is likely throttling running Furmark. Also, try something besides Furmark before you decide the extra shaders aren't giving you anymore performance.

 

[Mr. Pedantic]

Go into CCC and set the power control to +20. The card is likely throttling running Furmark. Also, try something besides Furmark before you decide the extra shaders aren't giving you anymore performance.

CRAAPP



Forgot about the throttling. Does it throttle 3DMark as well?

 

[cmdrdredd]

Shaders won't give higher performance right away. Only some games and software will have a boost. Overclocking is going to tap into the performance.

I set overdrive off in the catalyst control center and overclock using TRIXX. I found 1.18v @ 900x1350 to be the max stable clocks for my card. Every configuration is different so you have to experiment.

 

[3DVagabond]

People are always claiming the extra shaders don't make much of a difference. I believe this came from earlier less optimized drivers. It depends on whether or not the game makes good use of the shaders, but the difference has grown.

Here's some examples comparing the 6950 Toxic to the 6970. Keep in mind that the Toxic comes clocked at 880 core like the 6970 does RAM is slightly slower 5200 vs. 5500, that could acct. for some of the difference possibly, but Cayman hasn't appeared to be memory bottlenecked from O/C'ing reviews I recall.

10% is not uncommon in a number of games.

F1 2010 is an outlier showing better performance on the 6950 than 6970 :\

source hexus.net

 

[cmdrdredd]

Like i said, certain games benefit

 

[Silverforce11]

No, ram speed matters a lot on the 6950, boosting both core and ram to identical 6970 speed will result in 1-2% performance delta.

 

[Rhezuss]

It's the switch, I have the same card and flipping it gave my 128 Shaders and a sammich for free.

 

[Mr. Pedantic]

No, ram speed matters a lot on the 6950, boosting both core and ram to identical 6970 speed will result in 1-2% performance delta.

I agree, I've found overclocking memory gave a much greater benefit in terms of speed than core. It's still not much, but I'm at 890/1380 at the moment, and I'll probably stay here.