Let's face it, the real gains obtained with systems like this
in terms of frame rates are often irrelevant for many games.
Review sites show numerous games give good update rates with
just a single decent card, never mind a Crossfire/SLI setup.
And with driver issues meaning that some games respond poorly
to either Crossfire or SLI, it can be a bad idea if the game
you want to play is one of those affected.
Meanwhile, toms' own charts show that quite often a much
cheaper dual-card setup such as 4850 CF or 8800GT SLI gives
results that are just as good or better than more expensive
setups using 4870s or GTX280s.
In other words, if a game is already doing 80fps (eg. CoD4),
there's no point bothering with CF/SLI; if it's doing 30, two
cheaper cards will give the desired result; if it's much less
than that (eg. Crysis), better off waiting for new products
than spending a fortune on multiple highend cards that usually
won't deliver the desired result anyway and will be out of
date within 3 months because of new product launches and/or
price changes.
Very expensive setups are more about bragging points than
real gaming performance differences (I proved this to my own
satisfaction by getting superior 3DMark06 results a coupla years
back using an AGP X1950 system with a very cheap mbd, compared
to review sites that used much more expensive mbds with the
PCIe X1950). But hey, if you can genuinely afford it, then who
cares?
It's obviously fun. But if one is going to start
talking about price/performance then sure, the argument for
buying this sort of setup breaks down easily. I figure the
market for expensive systems are precisely those people for
whom price/performance isn't much of a concern.
Ian.