2 Slot Video cards and SLI

[imported_DanW]

In the gaming buyers guide published today Anandtech says:
"The other critical factor is that you will need to "downgrade" to a 6800GT. As the 6800 Ultra is a two-slot design, there will not be room to put two 6800 Ultras in a system - at least, not on the boards that we've seen. Two 6800GT cards are significantly faster than a single 6800 Ultra, though, so the tradeoff is worth it in our book."

On the other hand, Asus, has something else to say on the matter:
"Two PCI Express x16 slots placed too closely could block airflow, especially when the graphics cards are designed to take up a two-slot space in thickness. Bad air ventilation raises system temperature, which in turn affects system stability and shortens component life cycle.

The A8N-SLI Deluxe included a special design in which two PCI Express x1 slots are placed between the two PCI-E x16 graphics slots, permitting more room for ventilation compared with conventional SLI designs. This thoughtful layout has proven to increase airflow and lower the temperature."

Oops.

 

[TheStigma]

Its all about the physical layout. If you can physicly fit two cards in there without them colliding, and keep them from overheating, thats all you need. Different SLI motherboards have differing spacing between the PCI-E slots, so just get a motherboard that fits your need I suppose. I do hope that the SLi bridges are included with the motherboards, or else Nvidia gotta get a flexible-link developed post-haste =)

If your one ofthose poor souls who still rely on air-cooling then I agree that you need to be careful about running a SLi-setup, regardless of how much space you got to work with. unless cooling is overly powerful, or has an exhaust system wich dumps the hot air out of the case (like the artic cooler) you are going to get a LOT of heat produced in a relatively small area.

2x6800GT will net you aprox 105 watts. (full load)
2x6800ultra will net you a even heavier 144 watts. (full load)
In comparison, a new 90nm winchester core @ 3500+ produces about 150watts. (full load)
of course much more power-hungry CPUs out there. A P4 3,4gig can eat up as much as 235watts (full load).

summing this up, you can see that you might need as much as 300watts to cover for the CPU and SLI alone in a brand new AMD system. I'd say this more than warrants the purchase of a good 500w PSU minimum. After all,you have other units that also draw some juice, and you want some overhead. Personally I plan on going for watercooled 550W unit to cover my power-bases, but you could probably get away with using a GOOD 400watt unit too...even with 2xultra.

Hope this was helpful =)
-Stigma

wattage data sources:
http://www.xbitlabs.com/articl...y/ati-vs-nv-power.html
http://techreport.com/onearticle.x/7417

 

[LTC8K6]

A P4 3,4gig can eat up as much as 235watts (full load).

No it can't. That was the power for the whole computer. (He said yet again........)

 

[imported_DanW]

Originally posted by: TheStigma
Its all about the physical layout. If you can physicly fit two cards in there without them colliding, and keep them from overheating, thats all you need. Different SLI motherboards have differing spacing between the PCI-E slots, so just get a motherboard that fits your need I suppose. I do hope that the SLi bridges are included with the motherboards, or else Nvidia gotta get a flexible-link developed post-haste =)

SLI motherboards will ship with the link connector.

 

[Thermalrock]

Originally posted by: TheStigma

In comparison, a new 90nm winchester core @ 3500+ produces about 150watts. (full load)

bs.

 

[LTC8K6]

I wish no one had ever posted those system power numbers. They are all over the place being quoted as processor power numbers to the detriment of both AMD and Intel.

Of course it is not really the fault of the sites that posted them. They are clearly marked.