After reading several helpful posts on this forum I decided to try an ATI card in my new system instead of nVidia. My previous experiences with ATI have been quite poor but I respect the knowledge of those who posted positive reports so I gave it a shot.
The first card (5970) worked very well with Vegas - timeline playback, even with track motion, was mostly real time. The card apparently had issues - my new computer had fatal crashes when the monitors went to sleep. We RMA'd the first workstation.... And the replacement had the same issue. So we replaced the memory.... Same issue. Today we replaced the 5970 with an R9 290 and the timeline playback performance is even better.
I shot a Very Crude iPhone video that shows the difference with the GPU vs CPU:
The first card (5970) worked very well with Vegas - timeline playback, even with track motion, was mostly real time. The card apparently had issues - my new computer had fatal crashes when the monitors went to sleep. We RMA'd the first workstation.... And the replacement had the same issue. So we replaced the memory.... Same issue. Today we replaced the 5970 with an R9 290 and the timeline playback performance is even better.
I shot a Very Crude iPhone video that shows the difference with the GPU vs CPU: