[reader50]

No one else seems to have noticed this. But the new PowerMacs appear to be SLI-ready to me.

The PCIe slots:
4x
8x - 2nd SLI card
4x - this space normally has a slot-reconfig card in PCs.
16x - primary graphics card

The slot-reconfig card in PCs splits a single 16x slot into two 8x slots. Not needed here because Apple already provides a good 8x second slot.

Then I took a look at the pictures Apple provides for the new video cards.

6600 upgrade kit:


Quadro FX 4500


In both pics, you can just make out the standard SLI tab on top of the cards. So drop by NewEgg and get an SLI Connector Bridge for $15.
ps - does anyone else think the $200 card and the $1700 card look an awful lot alike?

It certainly looks to me that Mac SLI only needs driver support to work. Apple hasn't said anything about SLI one way or the other. Perhaps some lucky stiff with dual 6600 cards can give it a try. Benchmarking has shown that two cards in SLI will absolutely cream a single card of the same type.

[Big Mac]

There is certainly the hardware potential for SLI, but the software part of the equation is the difficult nut to crack. And as far as the two cards looking similar, they may well be identical. The only thing that makes the cards workstation cards are the special drivers, AFAIK.

[blizzard]

I believe the cards are largely similar, but with a few hardware differences that only soldering can bridge (at least, on the old cards...one of my friends soldered his Geforce into a Quadro a couple of years ago).

In any case, the only two slots that could be used for SLI on the Power Macs are the x4 slots, since SLI requires the two slots to be identical. One of the slots is x16, the other is x8. Most PCs using SLI use x8.

I'm paraphrasing what I read earlier today on Anandtech.

http://anandtech.com/weblog/default.aspx?bid=255

[reader50]

Regarding the two 'cards' looking much alike, I was referring to something different. It looks to me like Apple reused one of the pictures. Down-resed it, rotated 90 degrees. Even the fan logo and blades appear to be in the exact same spots.

I read the same thing on Anand's weblog. But ... I'm under the impression that current cards do not saturate an 8x connection. If so, the extra bandwidth of an x16 slot would not matter.

According to Apple's benchmarks, the Quadro FX 4500 is marginally faster than the 7800 GT, therefore it is based on the 7800 design. Perhaps it's a modified 7800 GTX. The 6600 comes from the 6800 family, so you would not be able to turn one of these cards into the other.