How to calculate kh/s of an unreleased card?

[gpucoolingmethod]

The upcoming Rx cards are supposedly going to smash records on the price/performance ratio.

Given that all their specifications are known how can one calculate their hashrate???

(with exact same settings of course)

[Gator-hex]

Number of stream processors units (SPUs) is usually a good guide.

HD7850 = 1024SPUs
HD7970 = 2048SPUs = 2x as fast.
2x HD7850s = 1024+1024SPUs = as fast as a HD7970

[gpucoolingmethod]

Number of stream processors units (SPUs) is usually a good guide.

thanks anything else i can use?

[Gator-hex]

Number of stream processors units (SPUs) is usually a good guide.

thanks anything else i can use?

Yes, don't forget to look at the max TDP Watts, it's a good guide on which is most power efficient.

All take power from the Motherboard = 75W
6-Pin PCI-E power connector = 75W
8-Pin PCI-E power connector = 150W

HD7850 = 1024SPUs = 150W max = 6.83SPUs/W
HD7970 = 2048SPUs = 375W max = 5.46SPUs/W

Therefor you should find 2x HD7850s give the same hashing power for 25% less watts.

[gpucoolingmethod]

Number of stream processors units (SPUs) is usually a good guide.

thanks anything else i can use?

Yes, don't forget to look at the max TDP Watts, it's a good guide on which is most power efficient.

All take power from the Motherboard = 75W
6-Pin PCI-E power connector = 75W
8-Pin PCI-E power connector = 150W

HD7850 = 1024SPUs = 150W max = 6.83SPUs/W
HD7970 = 2048SPUs = 375W max = 5.46SPUs/W

Therefor you should find 2x HD7850s give the same hashing power for 25% less watts.

good to know this formula although this isnt what Im asking for.

Im asking how to calculate kh/s of a card not its efficiency