Crossfire vs SLI vs Single Card Motherboard

++++ Answer the poll after you read this post completely++++


I will be building a new PC for one of my friends (He is paying for the parts and i get $150 for building it ) he wants a Crossfire Enabled Motherboard. I was wondering if this is a good thing to do. He wants the absolute best gaming system btw. He has about a $8k budget. (Wish I had that kind of money )

So here are the questions i have for you all:

1. Which is better for gaming SLI or Crossfire?

2. What are some good SLI and Crossfire motherboards?

3. Is it better to go with one graphics card such as the 8800 or an X1950?

4. Will you notice any difference in performance?

--------------------------------------------------------------

Here are the other parts:

Intel Core 2 Extreme QX6700 2.66GHz= $1000
Seagate Barracuda ES ST3750640NS 750GB= $400
Western Digital Raptor X 150GB 10,000 RPM=$230
NEC 20.1" 6ms DVI Widescreen LCD Monitor= $570
Thermaltake Armor Silver Aluminum ATX Full=$180
ENERMAX Liberty ELT620AWT ATX12V 620W(SLI Certified)= $150
ZALMAN 9700 LED 110mm= $55
OCZ FlexXLC Edition 2GB (2 x 1GB) Kit = $264
Microsoft Windows Vista 32-Bit Ultimate for System Builders= $200
*ALL PARTS MUST BE FOUND ON NEWEGG.COM*

That is what i plan to put in this system. I left the Motherboard and Graphics card blank because that is what i need to decide. SLI vs Crossfire vs Single Card.

All other suggestions are welcome.

He wants this PC finished by March 23. Please hurry.

if he wants it finished by Mar 23 then 2x8800GTX in SLI will slaughter any current Crossfire setup.
Whether he needs that power will also involve what he is displaying it on - if he isn't playing at seriously high res (2500x?) then he may not need it.

So, if we say that he's going 8800GTX SLI then he ought to go 680i (he has the budget).
Next decision is reference 680i mob (BFG, ECS, eVGA, Inno3D etc.) or non-reference - Asus Striker, abit IN9 32X, Gigabyte 680-DQ6 etc.
Currently I would go for the abit but preview rumours of the Gigabyte are good.

Ok, thanks for your help. He said he will wait until June/July for a new build.

If he's waiting until then, the R600 should be out and it could very well beat whatever Nvidia has at the time. I also wish that both Nvidia and AMD/ATI would use the same board so we consumers could make a choice based on what's the best card at the time without having to buy a special motherboard to support that card

That depends; how much other hardware are you running? My computer would need a 850wt psu if I ran two 8800 GTXs. You may not have as much hardware, so you might get by with less. Then again, if you're really thinking future proof, you should be thinking of a psu of at least 750wt size. It doesn't make sense to me why so many people want to think about as much hardware as they can buy, yet want to skimp on the psu.