Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Borman

macrumors member
Original poster
Aug 29, 2006
49
0
I know 2x 3870's would be faster in general (for Windows gaming), but if I remember correctly, the 2006 Mac Pro would be limited to 8x for the PCI-e side. Has anyone done a benchmark using the 2x Crossfire Setup vs a 8800GT? If I had to guess, the 2x CF would still come out ahead, but I just question how much the performance would be hurt (and my wallet) to make it worth it. Thanks a lot guys.
 
The 2x3870 would definitely be faster. I'm currently running 2x3870s in crossfire on my Mac Pro (first gen) with each on an 8x bus. Toms Hardware did some benchmarks a while ago with the 3870 in regards to 8x and 16x bus widths. If I remember correctly, they discovered that they had a drop in performance of (approximately) 7% when going from one card with 16x to one card with 8x. However, they also discovered that when going from crossfire 2x16x to crossfire 2x8x, there was also only a drop of about 7% when the logical assumption would have been for a 14% drop in speed.
So, in practical terms, the difference in PCIe links makes relatively little difference. 2x3870s on 8x PCIe links will be faster than a single 8800GT on a 16x link.
 
The 2x3870 would definitely be faster. I'm currently running 2x3870s in crossfire on my Mac Pro (first gen) with each on an 8x bus. Toms Hardware did some benchmarks a while ago with the 3870 in regards to 8x and 16x bus widths. If I remember correctly, they discovered that they had a drop in performance of (approximately) 7% when going from one card with 16x to one card with 8x. However, they also discovered that when going from crossfire 2x16x to crossfire 2x8x, there was also only a drop of about 7% when the logical assumption would have been for a 14% drop in speed.
So, in practical terms, the difference in PCIe links makes relatively little difference. 2x3870s on 8x PCIe links will be faster than a single 8800GT on a 16x link.

WOW!!!
Good thing I bought ATI 3870, BUT I'm still waiting for mine. It's been two weeks since I ordered mine from shop.ati.com . I CAN'T WAIT ANYMORE!!!
 
I didn't find the answer to life but I found the answer to the above post! But feel free to provide the link anyways!
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.