GPU & running dual OS systems?

[AfterglowMP]

Ah, it's a curse but I have to keep FCP7 going for some clients even though I'm organising to update my Mac Pro (6 core, 3.3mhz 2010, 24gb RAM, GPU ATI Radeon HD 5870) and move to Resolve/FCPX.

So my plan is to preserve the old system completely as is (OS 10.8.6) on a separate drive and instal El Capitan on new drive and switch back to the older system if I have to use the Final Cut Studio (I've heard it opens and works in El Capitan but don't want to rely on this).

But if I replace the old graphics card with something much faster like the Nvidia GTX 980TI, will the old system start up? I don't have space to have 2 graphics cards in the PCI slots but the 980 will only work with the more recent OS. Or is it that it will work but it won't go as fast as in a newer system?

 

[h9826790]

Ah, it's a curse but I have to keep FCP7 going for some clients even though I'm organising to update my Mac Pro (6 core, 3.3mhz 2010, 24gb RAM, GPU ATI Radeon HD 5870) and move to Resolve/FCPX.

So my plan is to preserve the old system completely as is (OS 10.8.6) on a separate drive and instal El Capitan on new drive and switch back to the older system if I have to use the Final Cut Studio (I've heard it opens and works in El Capitan but don't want to rely on this).

But if I replace the old graphics card with something much faster like the Nvidia GTX 980TI, will the old system start up? I don't have space to have 2 graphics cards in the PCI slots but the 980 will only work with the more recent OS. Or is it that it will work but it won't go as fast as in a newer system?

No, AFAIK, 980 won't work in 10.8.6.

For 10.8.6 and FCPX, you can consider R9 280X, (Or R9 280 if you worry about the power draw).

 

[AfterglowMP]

I'm not familiar with the R9 280X and have done a search. What would you say are the advantages of it given my kind of usage?

 

[h9826790]

There are lots of thread about 280x in this forum. It's one of the best performing card in FCPX with native driver support, and it's cheap.

The down side, you have to think about how to power it (the 8pin).