PowerColor HD7950 3GB GDDR5 (V2)

If you're planning to get the PowerColor HD7950 3GB GDDR5 (V2) with dual fan, make sure that your power supply has a 8-pin PCI-Express connector.

 In the Powercolor website it says the card has two 6-Pin PCI-Express Power Connectors. However when I opened the box the card is actually using x1 6-Pin and x1 8-Pin connector. So it is using the same power connectors as the PowerColor HD7970 cards.

I'm guessing this is because the new version of the card has a higher power draw than the previous version. Maybe for better overclocking or because of new BIOS / firmware the card is using? Anyway just make sure your PSU has the necessary PCI-Express connector.

Powercolor HD 7870 Vertex II VS Powercolor HD 7870 Myst Edition

Which is better Powercolor HD7870 Vertex II with higher engine clock rate because its OC already or the new Powercolor HD 7870 Myst Edition with lower engine clock speed but higher memory clock speed and UEFI ready?

I believe the Myst Edition is better. It is based on Radeon 7950/7970 GPU (Tahiti LE) so it has more shaders and has PowerTune with Boost (975 MHz). The memory is faster as well at 1.5GHz (6GHz effective). Based on reviews, when overclocked the card reaches 1.2GHz core speed and 1.6GHz memory speed.