wich 6970 card is better for SHA-1 calculation? see specs inside

[Alinus]

Hi.
I am interested in purchasing some 6970 cards for sl3 bf calculation.
i know that at this moment ocl-hashcat lite does not support it, but, nonetheless, i would welcome your advice.

i've seen that there are several versions of Gigabyte 6970 cards available (they seem to have a better 3 coolers system than the original one):

1. with ATI Radeon HD 6970 processor 900 mhz and 2gb ddr 5 memory, 256b bus.

2. with ATI Radeon HD 6970 processor 880 mhz and 2gb ddr 5 memory, 256b bus.

3. with ATI Radeon HD 6970 processor 900 mhz and 1gb ddr 5 memory, 256b bus.

4. with ATI Radeon HD 6870 processor 915 mhz and 1gb ddr 5 memory, 256b bus.

wich one should provide the better speed for a sha-1 calculation in your opinion?
and another question, does a PCI-E 2.1 card works on a PCI-E 2.0 slot?

[blazer]

1. with ATI Radeon HD 6970 processor 900 mhz and 2gb ddr 5 memory, 256b bus.

3. with ATI Radeon HD 6970 processor 900 mhz and 1gb ddr 5 memory, 256b bus.



1 and 3 are good, 6970 = More shader process @ higher clock speed = Faster.

I doubt the memory size makes much of a differences, probably look at the price difference?

[Alinus]

thanks.

how is it that there are 6970 boards with 6870 gpu's?

i need to crossfire this 6970 with a 6990 that i already have. wich one should work better in this configuration from the above?