From what I can tell, all Nvidia GPUs do this in Vegas using NVENC. My GTX 970 did it as well... though it isn't exactly what I'd consider a "slow down" in performance, it would render a group of frames incredibly fast (sometimes even faster than my much more capable Radeon 7) before pausing. It likely has to do with data being loaded in and out of some sort of buffer like MusicVid mentioned, I wouldn't worry about it. You likely are getting as much performance out of the card as you can.

Thanks to both of you. I am working on getting the file info.

fr0sty, this appears to be abnormal in my years of using the software. The pauses in between rendering a few frames are probably about five seconds, renders for two more seconds, and then pauses again. Its hard to believe that this is the maximum speed a 2070 card is capable of, especially with minimal fx, color grading, etc. Even with none of those things enabled, it still does it.

Here are the file properties:

Type: AVC
  Size: 163.96 MB (167,893,759 bytes)
  Created: Wednesday, June 5, 2019, 7:14:52 PM
  Modified: Wednesday, June 5, 2019, 7:20:45 PM
  Accessed: Wednesday, June 5, 2019, 7:20:45 PM
  Attributes: Archive

Streams
  Video: 00:02:41.428, 29.970 fps progressive, 1920x1080x32, AVC
  Audio: 00:02:41.364, 48,000 Hz, Stereo, AAC

Summary
  [TCFM]: 6

ACID information
  ACID chunk: no
  Stretch chunk: no
  Stretch list: no
  Stretch info2: no
  Beat markers: no
  Detected beats: no

Other metadata
  Regions/markers: no
  Command markers: no

Media manager
  Media tags: no

Plug-In
  Name: so4compoundplug.dll
  Folder: C:\Program Files\VEGAS\VEGAS Pro 16.0\FileIO Plug-Ins\so4compoundplug
  Format: AVC
  Version: Version 1.0 (Build 8532)
  Company: MAGIX Computer Products Intl. Co.

@Leon-R This is a known "issue" with Vegas. I put "issue" between quotes as it is not bug, but it is just the way Vegas rendering behaves due to the Vegas sw architecture, and/or VEGAS drivers. Your system is not to blame. I have the same issue, and just now I have proof that the NVIDEA can render much faster and smoothly instead of in bursts, all on the same system: I just upgraded magix sister NLE product Video pro X, and rendering a 4K source file (without any edits) to HEVC is incredibly fast and smooth as compared to Vegas on my PC.

This was the best proof to me that there is no HW bottleneck somewhere in my system (even if there would be some bottleneck, it can apparently be mitigated through different coding).

@bitman “I put "issue" between quotes as it is not bug,”

Well, if its not a bug? then its poorly implemented in Vegas Pro, given we now know, thanks, that it can be done better.

Have you done a render time comparison? Is the stop go leading to slower render times than it should be?

Just saw your “much faster” part, can you give us say what percentage difference, thanks.

The delay doesn't happen in other editors nor transcoders, so it's something they could possibly fix in a future version, although i'm not sure the magix crew are capable. Maybe a licencing issue? They can provide addons, and new features but the basic 'engine' is not within their expertise, and why it's never changed since the accusation from sony

Well, I decided to check it out myself, I downloaded a trial version of Magix Video Pro X.

I tested mainly Hevc. and confirmed that it had Hardware acceleration enabled in settings.

I used a source file of 27s 4K UHD 25fps rendered to 4K uhd, 25fps, the resultant data rate and size  matched very close for both programs.

The slight hesitancy was still obvious in VP compared to Video Pro X while rendering.

Render times ...

Magix Video Pro X.   0:50s

VP 16                         0:28s

Update:  I confirmed that the HW Acc. is indeed working, (its a trial version) by disabling it in settings.

The render time then went from 0:50s to 2:28s.

So VP is still faster to render even with 'stop and go'?

It would appear so, unless bitman has some further imput? re: “much faster?

@Former user Much faster in the case: no edits on the source file (source file is 4K 25P from Sony RX10 mark3, duration: 1 minute 8s) rendering all default settings on both Vegas and Magix video pro X11 to HEVC.

rendering time Vegas 16: 79s

rendering time MPX (11): 46s

so (almost) double the speed

@Leon-R

@ryclark

You can see the effect of stop and go of Vegas rendering (spikes), right picture.

The left picture is MPX 11 rendering

Note that the utilization percent of the video encoding of Vegas rendering is not representative as it is a momentary snapshot, the utilization with the spikes goes wildly up and down anywhere between 12% to 89%

It is not all roses with MPX however, rendering the same file into MPEG4 I would assume they use nvenc, but that is a no, the encoder window in the windows resource manager stays frightfully empty... Also the rendering took a whopping 3 minutes and 30s. Not sure that is indented or a bug.

Rendering in Vegas to Magix AVC with NVENC took only 1 minute and 13 s, so almost real time, and the nv encoder was used (albeit with spikes again).

MPX seems slower with timeline edits when using plugins, and also when rendering out with plugins and edits, even in HEVC, but this will take more investigation.

I would like to conclude that there is room for improvement in the software, for both Magix' NLE's.

@Leon-R @ryclark @bitman @Former user 

So, the plot thickens.  I realised it may have not been the smartest way to do this testing by using a source file of XAVC-I .mxf type.  For some reason this ALL-I file type must give a big render advantage to VP16, perhaps its better optimised for it.

I now selected a Panasonic GX80 4K UHD 25fps clip, ~0:19s duration for re-doing this test again, staying with HEVC as output codec.  Origional file size is 219mb and data rate is ~96.5 Mb/s.

Using default settings for both VP and VPX will give different Data Rates and resultant file sizes, so I modified the default VP Nvenc template to closely match the VPX output.  All output was 4K UHD 25fps.

The resultant file sizes were VP16/VPX … 84.9/84.0 mb

The resultant data rates were VP16/VPX …37,332/36,905 kbps

The resultant render times were VP16/VPX … 16/11s

So now VP16 is slower, perhaps because of this stop go issue in VP.

RE: VPX mp4 h264 encoding. Enabling/disabling HW encoding in the advanced section of the mpeg-4 section makes no difference to render times.  So in VPX you'r out of luck if you want to use it.  I tested VP/VPX render times, obviously VP with and VPX without HW encoding.  Results.. VP/VPX 12/38s.  Again I modified the render template to get similar data rates and file sizes.

 For all of the intermediate rendering below I assume it would be CPU only, no HW encoding.

As an aside I rendered out an Intermediate 422 HQ, the VP/VPX times were .. 1:22s/1:29s but I noticed that the data rate and file size for the VP16 render was smaller.  Looking at mediainfo the codec id's are VP/VPX APCN/APCH. 

I don't know Video Pro X can render any better or not. But a 20s GH5 10 bit 4K 30P footage render in Hevc finished in 12s for me.

Hi @BruceUSA, thanks, but I think this start stop hardware encoding issue is confined to Nvidia, not Amd, so therefore you should get better, smoother hardware encoding of h264/h265.

Hi @BruceUSA, thanks, but I think this start stop hardware encoding issue is confined to Nvidia, not Amd, so therefore you should get better, smoother hardware encoding of h264/h265.

Right. I hope VP17 will address the issue with Nividia card. VP17 need to find a way to use those RTX cards more effectively to increase the performance in both area, TL and Rendering.

Agreed.

I noticed that although the VPX and ffmpeg render times are much better than VP16, the quality for VPX was poorer using thee SSIM and PSNR tests.  I did the test once more, but similar results. 

As an aside, for fun, I also tested to see what the quality difference was between with and without HW encode, again using ffmpeg's SSIM and PSNR, tested on laptop.  Really, according to these tests very little difference, but an enormous 80 to 1 render time ratio.  Of course eyeballing the playback may show a bigger difference?

All tests used the same 4K UHD 25fps 219mb 96.5 Mb/s 19s duration source.mp4 clip as in previous post.

I've deleted my previous post as this summarises it better.

Hi everyone!

So long time I questionned myself to know if my system was in cause or not... well, happy to know that I'm not alone to experiment this "issue".

I have a Quadro M2200 CUDA in lenovo P51 laptop (xeon 3,2Ghz with Intell P630 GPU) and I was always wondering why when I render under vegas with nvenc acceleration, I see these stops.

I tested with quadro specific driver, Lenovo recommend driver, Nvidia latest driver, always the same result...

So here are my results with Vegas 17 and Video Pro X:

As you see with video pro X, quadro card is nearly 100% loaded, nothing compared to poor performance with Vegas nvenc... actually, Vegas rendering is faster with integrated intel QSV GPU acceleration than with dedicated Nvidia Quadro M2200...

Any improvements to come with Vegas?

Vegas 17 advertise that it handles Nvidia GPU to render faster than ever... does it works only with some graphic cards or specifif drivers? Does anyone succeed rendering faster with Nvidia graphic cards? without stops?

They say "NVIDIA® GeForce 9XX Series or higher with 4Go" which means it should works like a charm for all of us no?

Vegas 17 advertise that it handles Nvidia GPU to render faster than ever... does it works only with some graphic cards or specifif drivers? Does anyone succeed rendering faster with Nvidia graphic cards? without stops?

Look for the cards at the specs for this program and the deveoppers told us to use the latest STUDIO drivers.
I have very fast rendering on desktop from signature

They say "NVIDIA® GeForce 9XX Series or higher with 4Go" which means it should works like a charm for all of us no?

More or less, the stronger the card and higher the amount of cores that can be used it workes faster than the lower types.

Vegas 17 advertise that it handles Nvidia GPU to render faster than ever... does it works only with some graphic cards or specifif drivers? Does anyone succeed rendering faster with Nvidia graphic cards? without stops?

Look for the cards at the specs for this program and the deveoppers told us to use the latest STUDIO drivers.
I have very fast rendering on desktop from signature

Hi j-v! unfortunately studio driver are not suitable for nvidia cuadro M2200 card... so what you are saying is that with these studio drivers you don't have the 2s stop rendering issue?

No, not with the GTX 1660Ti on desktop nor the GTX 1050 on laptop. Fast and good rendering through NVENC and fast decoding through NVDEC(only in VPro 17)