Yeah, I already got it. Now in Cyntrix hand, am watercooling it, hopefully I have your luck to get a golden card. If everything goes well on my 5670x1080, I might just give up cross firing it. 

For a single 7970 never an issue for high clocks. BUt for gaming 1.2Ghz is very suitable. Above that occasionally you would have artifacts

If you do a CF 7970 then you may need to individually set the clock for each card. your results would vary.
Hence the asic score is cruical when doing CF if you are lazy and like to same settings for all. Also normally the lower the asic the lower the voltage you need to set the card when overclocking

For 5780x1080 depends on your settings and your eye. If you like to play at high settings would not be possible
New games are full utilizing the max capablity of the new top end cards

Max payne pushs the limits on the graphic card same with witcher 2

for max payne if you are using 1920 x 1080 on max settings, without AA , you would need 2890 Mb of graphic ram
if you are playing max settings with 8x ( max aa) you would need 6100 mB of graphic ram

Max payne in the settings menu has a readout that reads you memory needs

7970 cards has various issues but its a really good buy if you are going for full block watercooling.
standard has too many issues, too hot, noisy, and above 60C the cards is not so stable when overclocking. You can read on the forums and experience it your self. also memory heat is really important hence the full block. chances for artifacts to happen increase exponentialy with memory. If you overclock it, higher chance of artifacts same with the heat.

using trifire 7970 so i am full aware of the limitations of the cards. So far until before max payne, the card is quite crap versus the 680. After max payne it starts to really shine. 680 still beats it on frames per second.

If you are buying a 7970 don't buy the reference card unless you want to overclock. actually don't buy would be best. Just buy like the dc2. The reference card is way too noisy and hot. Now with dc2 cards there are waterblocks for it. Plus resale value for reference cards are super low

i bought my last 7970 at rm1200. brand new was 1750.

Got to do with the vram. the 680 does not have enough for vram, multiples scenes do stress out the card without sufficient vram