Hi guys,
I have a MacPro 2012 with Radeon 7950 card and when that card is working at almost 100% load (shows iStat Menus) some graphical tasks are completed 10 times faster compared to using the CPU only. But in the real world, for instance during rendering in FCPX the GPU is not working at 100%, but jumping between 25% and 75%, and maybe 50% load overall. How should I interpret that?
Let's say rendering without GPU takes 60 seconds, then optimal rendering with the GPU at 100% will be 10 times faster, 6 seconds. How fast will it be when iStat Menus shows the GPU is working at 50%? Is it just half slower so the rendertime becomes 12 seconds? Or is the GPU idling half of the time so the render time becomes 30 seconds CPU rendering plus 3 seconds GPU rendering for the remaining other half, totaling 33 seconds?
And what happens when I replace it with a 2 times faster card? Will it cut the render time to half in 6 seconds? Or will it also idling half of the time so the render times becomes 30 sec + 1,5 sec, totaling 31,5 sec? Or will there be hardware or other throttling and will the 2 times faster card simply work at 25%...
I understand that there is no straight answer, because it depends on a lot of things like how the software is written. But it comes down to this: in my case FCPX is the program that uses the GPU the most. But usually around 50%. Does it make any sense to buy a faster GPU if the 7950 is already almost never working on its full speed? If the GPU is only active half of the render time then the profit of a faster GPU totally falls away against the remaining slow CPU render time. Or do I completely interpret that 50% GPU load wrong?
I have a MacPro 2012 with Radeon 7950 card and when that card is working at almost 100% load (shows iStat Menus) some graphical tasks are completed 10 times faster compared to using the CPU only. But in the real world, for instance during rendering in FCPX the GPU is not working at 100%, but jumping between 25% and 75%, and maybe 50% load overall. How should I interpret that?
Let's say rendering without GPU takes 60 seconds, then optimal rendering with the GPU at 100% will be 10 times faster, 6 seconds. How fast will it be when iStat Menus shows the GPU is working at 50%? Is it just half slower so the rendertime becomes 12 seconds? Or is the GPU idling half of the time so the render time becomes 30 seconds CPU rendering plus 3 seconds GPU rendering for the remaining other half, totaling 33 seconds?
And what happens when I replace it with a 2 times faster card? Will it cut the render time to half in 6 seconds? Or will it also idling half of the time so the render times becomes 30 sec + 1,5 sec, totaling 31,5 sec? Or will there be hardware or other throttling and will the 2 times faster card simply work at 25%...
I understand that there is no straight answer, because it depends on a lot of things like how the software is written. But it comes down to this: in my case FCPX is the program that uses the GPU the most. But usually around 50%. Does it make any sense to buy a faster GPU if the 7950 is already almost never working on its full speed? If the GPU is only active half of the render time then the profit of a faster GPU totally falls away against the remaining slow CPU render time. Or do I completely interpret that 50% GPU load wrong?