Renerding with GPU acceleration slower than CPU only
 

I was excited about the faster rendering capabilities advertised with Vegas Pro 11, so I upgraded my video card (NVIDIA GeForce GTX 570). It's great when editing. Best quality works great, even when scrubbing at the highest speed. Rendering, however, is a different story.

My computer is a beast. Quad core Intel i7 975@3.33 GHz. 12GB of RAM. Solid State HDDs. I built it this way to squeeze every ounce of speed out of rendering the long-form events I produce (typically 90 minutes or more). Prior to v11, the CPU would max out at 99% and the fan would run loud. And I could render a 720p DV project with 32-bit floating point a little faster than real time. A 90 minute project would render in about 80 minutes.

I was very excited at the prospect of adding some GPU horsepower and rendering in even less time. However, that is not the case. With the GPU acceleration enabled, my projects are taking about 50% more time to render. A 2 hour project takes about 3 hours to render. The CPU is maxing at only 21%, and it's very quiet. I suppose this is good if I want to multi-task, but that's not what I want.

Is there any way to use GPU acceleration AND max out the CPU as well? Or do I need to disable the GPU acceleration when rendering?

Re: Renerding with GPU acceleration slower than CPU only
 

I noticed the same thing Jerry. My system is a dual x5650 xeon system, which use to run 16 threads at 78% in vegas 10. Version 11 seemed to use the video card so much and ignored all the power of the system. I was like wow, this kinda sucks. Now I have not tested to much further, but have noticed one thing. If I take a version 10 project and drop it on the vegas 11 time line it does seem to be slower. But if I make the project from scratch starting in vegas 11 it seems to be faster. Now maybe I am forgetting something but so far this is my way of sleeping at night...after buying such a system...

On the other hand, that NB Titler is worth the upgrade alone. Also the realtime playback is so much easier.

P.S. dont try and use your gpu to do to much else while you are rendering as it will cause it to slow down too. I tried playing a game in full screen, and watching the gpu usage in a smaller window on my second monitor to find out vegas crashed about halfway through. I do have two video cards, and setting vegas to use the 2nd one, would however allow you to do all kinds of things with the system, with no slowdowns.

Now that the cpus are using 14-17% I am not sure how I will heat my room in the basement. Sony owes me a heater now with version 11. Anyone know who I should hold accountable at sony for my loss of heat? :)

Re: Renerding with GPU acceleration slower than CPU only
 

Well . . . that can't surprise you, can it?

Re: Renerding with GPU acceleration slower than CPU only
 

No not at all. It was a test of common sense, just to see what would happen. o)

Re: Renerding with GPU acceleration slower than CPU only
 

I disabled the GPU and tried rendering the same 2 hour project as a Blu-ray, and it will take less time with the full CPU power behind it than the DV render did with the GPU accelerator. So, I pretty much answered my own question.

I suppose the GPU render is beneficial for those with less CPU power, or if you want to multi-task while rendering.

Re: Renerding with GPU acceleration slower than CPU only
 

I experienced some very strange glitches today when rendering, the preview window went haywire, all sorts of lines and insanity, cartoonish effects, it was truly strange. Disabled GPU and rendering is now fine.

I'm wondering if this is a symptom of a weak video card, or some other issue with my card. Not a big deal to me, but a very small disappointment. I'm wondering if the GPU needs to keep up with the CPU somehow, and it can't. Who knows, I am not a PC expert.

Re: Renerding with GPU acceleration slower than CPU only
 

I have found I have a bad video card. I suspect that Vegas will bring out the weaknesses of video cards that prior to this update might have gone unnoticed.

Re: Renerding with GPU acceleration slower than CPU only
 

Before installing a new version of Vegas I usually wait until at least the "A" release. However, this time I took the plunge and upgraded to Vegas 11 over the weekend and started a new project. I ran a few render tests today on my i7 930 with ATI Radeon HD5700 with the latest driver. The project is HDV 1080i 1440 x 1080 and is 13 minutes long. The only effects are an animated title and crossfades.

With rendering to NTSC Widescreen, my best render time was obtained with GPU on at 9:56 with 18-23% CPU utilization . With GPU off, 11:49 with 67-77% CPU utilization.

It was a different story with rendering to HD 1440 x 1080-60i. With GPU on, render time was 20:46 with 81-98% CPU utilization. With GPU off, render time was very slightly shorter at 20:42 with 95-100% CPU utilization.

In all cases rendering the title ranged from 18-30% CPU utilization.

Since I typically render to NTSC Widescreen, I'll leave GPU on. I hope with updates to Vegas 11 we'll see better utilization of the CPU and GPU. The main reason I upgraded to 11 was the acceleration, so I'm a little disappointed but still glad I upgraded. I really like the new titler choices.

Re: Renerding with GPU acceleration slower than CPU only
 

Jerry,

Ditto, in my case. And I don't use Vegas (PowerDirector). I see a 20 - 30 % improvement in speed using the raw power of the i7 PC. And I also find that the video image quality is also improved.

Re: Renerding with GPU acceleration slower than CPU only
 

I can't help you with your problem, but I really like the title of this thread, "Renerding with GPU acceleration slower than CPU only"

A typo or clever humor? Whatever, I had a chuckle.

...Jerry