AMD R9 GPU, faster edits, slower transcoding

Paul Anderegg wrote on 3/17/2014, 9:50 PM

just popped a brand new R9 270X ($250) into my i7-3770 PC. Before doing so, I ran some quick Vegas Press Release renders, as well as some AVC file transcodes.

Sony Press Release render speeds PRE/POST GPU install

XDCAM EX 2:11/0:42
MC AVC 3:02/2:40
S AVC 1080P60 1:27/1:17
XAVC S 1080P60 2:52/2:12

Wow, pretty good improvement across the board, even with the 1080p60 AVC stuff. Next, I wanted to know the transcoding performance improvement, which is what I use Vegas for 99.9% of the time anyway.

Basic transcode of previously rendered XAVC 1080p60 file PRE/POST GPU install

XAVC S 1080P60 1:57:2:06
S AVC 1080P60 1:46/2:27
MC AVC 1080P30 2:57/4:00

I was a bit baffled by these results, so I went through a series of activating/deactivating/restarting VP12's GPU status in Preferences. This had absolutely no effect. On or off, selecting CPU, GPU, OpenCL, or QuickSync, made no difference in the transcoding speed, it remained at the POST GPU install figures.

I am at a loss here. Obviously the GPU is working, as can be seen from the editing performance improvements, which are quite drastic IMO. Perhaps I have not configured something properly? Can anyone suggest some AMD set-up/settings tips to optimize Vegas for my transcoding requirements? I am currently set to iGPU as primary in the BIOS, and my monitor is hooked up to that integrated port. I want to only use the R9 for rendering/transcoding. I am going to play around with some XAVC 4K renderings just for fun, since I am going to be getting a Sony AX100 as soon as they ship.

Thanks guys! If anything, I hope this helps people figure out if the R9 270X is a worthy piece of hardware! :-)

Comments

hazydave wrote on 4/19/2014, 1:50 AM

Something sounds screwed up on your system. Can't say what for sure.

The Vegas rendering pipeline is going to be used for preview or render, so anything that makes your preview faster ought to be use for render. The one caveat: rendering adds "stuff" to your CPU/GPU load: specifically, the CODEC itself. Far as I know, none of the pro CODECs have any GPU acceleration.

Main Concept AVC does, internally, but it will absolutely not be used for the 270X, or any GCN or nVidia Kepler GPU. And for a very stupid reason: they have the chip IDs of the supported chips in the CODEC. If you're using a matching chip (like that of my HD6970... I get a 0.42s render on the Red Car Demo), you get OpenCL when set to OpenCL. If not, you just get CPU rendering. Period. Vegas itself may be using the GPU, but the CODEC isn't.

So why might a GPU render actually go slower(!) than CPU-only. Well, it's a mean trick, but using the GPU isn't free. There's a certain bit of CPU time needed to set up the OpenCL code, compile it, and schlep it and the data over to your GPU, and a bit of time getting the result back. So with just the wrong combination of GPU and GPU, it's possible.

It's a good idea to run a CPU monitor (Windows Task Manager) and a GPU monitor (GPU Shark) to monitor what's happening during a render. If you don't see significant GPU activity, you have some kind of problem. Probably drivers. But I don't know about the R270X itself. But check this out: http://www.tomshardware.com/reviews/radeon-r9-280x-r9-270x-r7-260x,3635-17.html

That implies that, with suitably correct drivers and all, you ought to be kicking my GPU's ass with your R270X on OpenCL stuff. Well, except for that last one... that's kind of freakish. I mean, other than that, and ensuring you really do have the new R270X selected in Vegas, there's not much else to tweak. So I'd check on the activity and look for a GPU being kept busy. Don't worry about MC AVC dropping, that's completely expected due to the limitations mentioned from Main Concept, not Sony's fault (well, other than allowing that to happen -- if they had just eliminated that GPU check, it would be working fine on newer hardware in all likelihood, that's kind of the point of OpenCL).

NormanPCN wrote on 4/19/2014, 9:27 AM

I am not sure why you would see slower time on your transcode.

The Sony benchmark project is very heavy on effects and this OpenCL code in Vegas runs very well on AMD GPUs.

What I do know is that...

Mainconcept AVC OpenCL does not support AMD GCN (graphics core next) GPUs. This means AMD 7xxx and R8/9 video cards.

It will always fall back to CPU only. In MC AVC if on the system tab in render as you click the check GPU button, it will say OpenCL is available. OpenCL is available but MC AVC OpenCL is hard coded to specific AMD architectures.

Sony AVC does use current AMD GPUs but it does not do very much with GPU so any speed increase is small.

monoparadox wrote on 4/19/2014, 9:51 AM

Norman,

Just so I'm clear. I am running a radeon 7800 series. I see GPU activity in CCC when running MC mp4. Is this only what Vegas is tapping apart from the MC transcoder? Is this also true of the Sony MXF transcoders? SonyAVC seems to hum right along using openCL.

Timline playback is nice.

tom

NormanPCN wrote on 4/19/2014, 10:02 AM

Vegas "proper" uses GPU. By this is mean the vegas video engine. This of course happens with playback and with render.

The problem with looking at GPU load is we do not know what it is measuring.

Playback is
render video stream, send to preview window(s)

Render as is
render video stream, send to file encoder.

Notice there is a common denominator in those two actions. The Vegas video engine and the Vegas video engine supports all GPUs.

You can turn Vegas GPU use off and still use GPU in MC AVC. I did with with my old 5850 card. I tested, and timed it four ways.

Vegas GPU, MC AVC OpenCL GPU
OFF OFF
OFF ON
ON OFF
ON ON

monoparadox wrote on 4/19/2014, 10:12 AM

Norman,

Thanks for your reply. It jives with what I'm experiencing. I was hoping Vegas 13 would address that issue. But then, like many others I'm coming to the conclusion it's a very minimalistic release.

tom

[r]Evolution wrote on 4/19/2014, 8:59 PM

I would rather see improvements during editing than during rendering.
- While editing, I'm there. While rendering, I'm sleeping.

monoparadox wrote on 4/19/2014, 9:57 PM

[r]Evolution--

Agreed. In that regard I'm pleased with my Radeon. Good playback and stable.

tom