Does open CL have a bottleneck then? Why are Sony and other developers promoting GPU acceleration if it isn't very helpful?

I have a NVidia GTX470 and it doesn't seem to make much difference rendering with it on or off in a number of programs that claim to be GPU accelerated. All that happens is the GPU fan speeds up and sounds like an aircraft coming in to land.

The power increase isn't noticeable like after upgrading a CPU for example. Is GPU acceleration the emperors new clothes?

I think its fashionable

seems as always its the cpu that makes the difference.

i bought all nvidia cards to use it on adobe mecury playback engine, it didnt seem to make any difference, over all disapointed with gpu acceleration or decelaration as experiance shows.

current project take over an hour longer to render gpu accelerated

Wrong, it uses either. Read here (on the RHS):

http://www.sonycreativesoftware.com/vegaspro/gpuacceleration

geoff

In the case of nvidia gpus, openCL is the method vegas uses to get to CUDA.

think its only the cuda enabled cards that have open cl, its the open cl that vegas use.

its a play of words sony doesnt use cuda using open cl allows it work with both ATI and Nvidia cards.

One of the confusing things for me is figuring out when a piece of software uses the GPU. I have After Effects which isn't CUDA accelerated but some of my AF plugins claim they are GPU accelerated which seems to be the case when the GPU fan cranks up to 11 and I have to strap the desktop down (exaggerating...almost.)

What I mean is, it's not clear to me how and when some of this software makes use of the GPU and considering many of us PC owners have different configurations of software/hardware then perhaps that's why it doesn't work that well. Although, it would be helpful to know for definite if it's pointless buying a high powered GPU card due to a bottleneck. It would save a lot of money - the price difference between a 560M and a 580M was £425 (incl. VAT) when I tried configuring a laptop at PC Specialist.

While Vegas seems to use CUDA directly for rendering, it uses OpenCL for preview and a lot of its filters. Some plugins also use CUDA directly, most notably Neat Video v3. Neat Video will also use multiple GPUs if you have more than one card installed. Lots of AE filters also use CUDA even though AE itself doesn't.

If you have a video card which is plugged into an x16 PCI-e slot, the interface can shovel data at an incredible rate. My thinking about video cards is the same as CPUs, buy the fastest one you can afford. In the case of video cards, the most CUDA cores and the fastest clock speeds. More and more software is taking advantage of GPU processing, so you're going to end up using all the horsepower you have. That now applies to both CPUs and GPUs. That's just my opinion.

I've been considering buying a new video card (to improve my performance even more) since my old one (GForce 9500GT) along with my trusty old CPU (Intel 8800 Quad) actually have better playback in Vegas 11 (with the new 425 build) than previous versions.

Previously I have been running Vegas ver 10e.

Now that I'm running Vegas 11 - 425, I was amazed that my old card and CPU would make enough difference in playback, that I would notice.

I have nice smooth playback now on "Best (Auto)" where before playback was always choppy unless I set it to "Preview (Half)" or even less on the multi-camera projects.

It has done this with all of the codecs/video types I use.

Any time I used track motion, pan & crop, or plug-ins in Vegas 10e, choppy playback occurred unless I dialed the preview back down to half preview, or even draft in some instances.

Now it's smooth sailing (on "Best" playback). Render times so far seem to be about the same, although I haven't rendered enough to really tell for sure.

Thanks, Will

I read somewhere on this forum that video processing can only access a maximum of 96 CUDA cores due to the limits of current cpu architecture.

Uh, no. It can access all the cores that you have. This is not something Vegas (or other software) has any control over. It just tells the GPU what to do. It is the GPU that allocates its cores as needed. The only way software could limit the number of cores used would be if it only asked the GPU to process an array of data with a small number of data items. So, to only use 96 cores, Vegas would have to process frames with just 96 pixels each.

A 1080p frame contains 1,920 x 1,080 = 2,073,600 pixels. So even if your GPU had 2,073,600 cores, Vegas could use them all with a 1080p video.