| PowerColor PCS+ HD6950 Vortex II |  |
| Reviews - Featured Reviews: Video Cards | |
| Written by David Ramsey | |
| Sunday, 22 May 2011 | |
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Page 5 of 17
HD6950 to HD6970: Unlocking Extra ShadersWhen the Radeon HD6950 cards were introduced, it didn't take enthusiasts long to figure out that they used the exact same GPU as the HD6970, only with some of the shaders disabled. While an HD6970 has 1536 shaders, the HD6950 has only 1408. By re-flashing the BIOS on a 6950 with the BIOS from a 6970, or using a tool such as TechPowerUp's "Radeon BIOS Editor", enthusiasts could enable the unused shaders and gain some performance. Most 6950 cards made it really easy with this little switch:
In the position shown, the card uses its standard, non-modifiable BIOS; moving it to the other position selects a second, modifiable BIOS. This removed worries about "bricking" a card with a failed BIOS update since you can always simply flip the switch to the original position and reboot. However, I wasn't able to unlock the extra shaders on this card. I tried flashing with several 6970 BIOSes as well as modifying the original BIOS with TechPowerUp's "Radeon BIOS Editor" utility. I could change parameters in the BIOS such as the default GPU and memory clocks, and confirm the changes with GPU-Z, but shader unlocking never worked. I suspect PowerColor (or perhaps AMD) has locked this ability out. PowerColor does offer a 6950-based card, the AX6950 PCS++, which comes with a 1536-shader enabled BIOS pre-installed on the card and accessible via the switch, but that card comes with 8-pin and 6-pin power connectors to handle the extra load, whereas the Vortex II Edition uses two 6-pin connectors. Benchmark Reviews examined the AX6950 PCS++ card here. Let's see how this card performs just as a 6950.
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Comments
Are there still new Radeon HD6950 cards out there that will unlock? I recall reading somewhere that a newer upcoming design would prevent that.
We see a lot of reviews of these aftermarket OC editions on BMR.com (like the powercolor Vortex range and MSi with their Hawk and Lightning variants etc) But they are always pitted against the stock standard cards - or at best older and inferior cards in a crossfire/sli config.
This is useful of course, but the enthusiast in me would love to see a battle royale pitting the best OC variants from Powercolor, MSi, Gigabyte and co. 'Head to Head' to see who makes the best variant of the HD6950 &/or the GTX560ti
Just a thought :)
Also, as you perform your tests, have you experience any hangs or crash?
A friend of mine is serious about buying this PC6850 2gig Vortex 2 card
although he's not into researching much about it on the internet for its real potential, perhaps this might be a good time to ask you so
i could tell him about the settings you used so he could used it on his
when he bought the card. And, if possible if you have tested the card
set to a much higher settings than the one you posted (930mhz and 1370mhz on memory) could you post it here including the voltage settings
and the performance it gained in percentage based from the stock. Thanks and God bless!
I did not have any hangs or crashes with the overclocked settings I used as long as I kept the fans running full blast. If I left the fans on "Auto", the card would not complete most of the benchmarks when overclocked.
The overclock I achieved was exceptionally high for a 6950. I would not expect most examples to be able to overclock this well. Luck of the draw and all that.
The performance improvement using the overclocked settings is not only noted in each benchmark test, but summarized in a table at the end of the benchmarking section.