How many Sapphire Sapphire RADEON R9 270X can i install in my mac pro 2009?

Question

How many of the graphics cards can I install in my mac pro 2009? Sapphire Sapphire RADEON R9 270X
Thanks

Answer 1

Why? do you use FCP-X? that will benefit from two. Also gaming in Windows where you can use Crossfire
You have two 6-pin power feeds so you will need a small 450W PSU - those come with two 8-pin and two 6-pin.
Those can often fit in the optical drive bay and cost $25-75 range.
"500W" is NOT for the card! that is the minimum PC PSU only!
when buying look for card that uses only two 6-pin and not an 8-pin power.
75W for the PCIe slot, and 150W from two 6-pin cables, most GPUs fall into the 200-250W at maximum stress levels8-pin is basically two 6-pins and 150W feed
> we CrossFired a pair of Radeon R9 270s in our 2010 Mac Pro tower. Under Windows 7 64bit Ultimate, it registered 145 FPS in the Diablo test.
http://barefeats.com/tube06.html
Keep in mind that the Mac Pro tower can't feed enough power to the dual 980s, dual 290Xs, or dual 7950s.
We used an auxillary power supply to compensate.
For the hard core GPU rendering, there are external expansion boxes with their own power supplies.
In an earlier article, we featured the Cubix Xpander which facilitated the connection of 5 GPUs to the Mac Pro tower.
If you favor an AMD GPU like the Radeon R9 290X, MacVidCards can modify it to run at PCIe 2.0 bandwidth in your Mac Pro tower.
The Sapphire Radeon R9 7950 Mac Edition is available from OWC and TransIntl.
February 6th, 2015 -- Dual GeForce GTX 980s vs other Dual GPUs running multi-gpu 'aware' apps
February 6th, 2014 -- (UPDATE) GeForce GTX 980 GPU versus 8 other GPUs running Games and OpenGL Benchmarks
January 29th, 2015 -- GeForce GTX 980 vs 9 other GPUs running Resolve, LuxMark, and Octane Render
December 28th, 2013 -- Does Final Cut Pro X 10.1 render faster on Mac Pro towers with Dual AMD GPUs? What about Motion 5.1?
Things to keep in mind:
The Radeon R9 280X we used was 'un-flashed.' It booted OS X fine but there was no startup screen. Also, when we checked the speed of CPU-to-PCIe-to-CPU communication, it appeared to be running in PCIe 1.0 mode instead of PCIe 2.0. However, unless the GPU intensive app saturates the PCIe 1.0 bandwidth, it will not run any faster in PCIe 2.0 mode. http://barefeats.com/tube12.html
Which is one reason why you might want to buy pre-modified cards from http://www.macvidcards.com