Phil, this isn't directly answering your question, but I think that SLI and 
Crossfire systems are a bit over-rated.  By this I mean that they really 
only find their purpose for someone who is building a top end system that 
will include more than one video card from its conception.  Most of us will 
get plenty of 3D horsepower from a single video card.  While you often hear 
the rationale that "I might want to add a second card later", by the time 
that a user needs more 3D rendering power, they will be better served with 
newer generation single video card, instead of trying to find a card to run 
in SLI or crossfire mode with their original card.

One of the problems with SLI and Crossfire is that the amount of boost in 
fps that you'll get by adding an additional card is highly dependent on the 
application being run.  If you are intent upon running a multiple video card 
rig, I'd suggest that you check the benchmarks that your favorite games 
achieve in SLI vs Crossfire configurations to help you decide which brand of 
video chip to go with.

Both ATI/AMD and Nvidia offer mutlichip single card solutions now.  These 
give you the benefits of a SLI or a Crossfire configuration on a single 
card.  Since they only use one slot, they will run on any decent motherboard 
with a 16x PCI-E slot.

Personally, if I were shopping for a system upgrade built around an Intel 
processor, I would stick with the Intel chipsets.  This will rule out SLI, 
but I wouldn't be concerned too much about that.  I would just pick the best 
single video card in my budget.  The prices have really fallen on the high 
mid-range video cards.  For example, I bought a 8800 GT back in January for 
around $260.  This still excellent card can be found going for as little as 
$160, now.  (I suppose at that price, picking up two of them for an SLI 
configuration doesn't sound that outrageous.)

I'm not sure that PCI-E 2.0 is an upgrade that most of us will be able to 
see any improvements from  It provides for higher throughput than original 
PCI-E motherboards, but I don't think many of us could point to any 
bottlenecks in their system's performance due to lack of PCI-E bandwidth.

John Sproule

--------- Original Message Below --------------


Date:    Fri, 30 May 2008 18:54:26 EDT
From:    [log in to unmask]
Subject: SLI vs Crossfire

I am collecting parts for a new build to handle intense gaming and 3D
applications. Though I won't be able to get the best ($600.00+ per card), I 
hope  to
do well in the $200.00 to 300.00 range. Probably will run an intel core two
duo initially perhaps upping to a quad at a later date (if this dosen't 
cause
problems with the OS). Will use XP though haven't decided on Home, Pro or
Media.

- My questions are what is the performance difference between Nvidia's  SLI
and Radeon"s Crossfire set-ups?

- Is there a great difference in the card's having GDDR2 memory as compared
to DDR2.

- Is the PCIe 2.0 a big leap over PCIe x16?

This will be a project that will start with one card only, adding the 
second
as I can afford it. I am researching elseware online but trust the  opinions
found on this list as well as the "low-tech" answers.

Thanks,
-Phil-

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