[Dave Lozinski]

What other files have you tried rendering to?

For me, I’ve always had to render the files to “m2v” with separate ACC audio.

DVDs require videos to be in mpeg2 format, so I’m not sure how well just straight mpegs work.

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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[Dave Lozinski]

[Matt Carlson] “I can put forth a theory here after reading several weeks of better than average PC builds choking on renders. The facts in this instance are pretty straightforward. System Ram = 12GB. Setting preview ram to 8GB seems reasonable since most only have 4GB to begin with (although 8GB preview ram is probably unnecessary in most work flows.) Once the preview ram is set to 0 or 128mb render times are cut buy a factor of ten or twenty.

A GTX 460 is a reasonable card and miles ahead of say a 9800gt and the 9800gt does a serviceable job. A difference of 50+ minutes down to 2 minutes suggests something to me. Vegas may be walling off CUDA cores to run the preview ram. When it comes to final rendering CUDA is not being released and whatever small amount Vegas is leaving open is being seen as the total of CUDA cores available. This may be some small amount like ten percent or less. With only a small percentage of CUDA cores available Vegas then begins to render inefficiently because the graphics card is seen as capable but has no power left. Under these circumstances the graphics card would actually be a major hindrance. Once the preview ram is optioned back to being insignificant the GTX 460 gets back to chewing on the render the way it should.

This is only a theory but it would explain the massive inconsistency in render times.”

Hey Matt:

Interesting theory! However I would say that’s not the case here because (and you wouldn’t have known this from what I’ve posted) when I first start rendering, Vegas zips through the video up until about the first 18%. Then it starts to slow down before doing like 1 frame per second.

So either it’s using the full amount of CUDA cores when it starts, or it always has the “reduced” amount as per your theory and for some reason stops using them later through the process?

One other thing I checked last night is in Task Manager I used the Resource Monitor to watch disk activity. There didn’t seem to be any noticeable difference whether I had the amount of dynamic preview ram set to 128MB or 9000MB. Eg, the disk queue length was always small. So to me, that says my hard drives aren’t being thrashed about either.

Two other changes I made to my system to see what that does is:
1) turned off the Windows Indexing Service
2) had it render out to my C drive

In both cases, with the dynamic ram set to 9000MB it eventually ground to a snails pace rendering; with 128MB it kept chugging along.

Hmmm… any other theories?

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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[Dave Lozinski]

I just updated to 511 and am not having any sort of memory issues what-so-ever.

I would double check to see what the amount of dynamic-ram preview memory you have set as Vegas will start to use that while going through its playback process.

If on Win7 go into Task Manager and then click on the Resource Manager and watch the tab for memory. See what happens there as it lists the amount used, amount allocated to processes, amount reserved, etc etc.

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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[Dave Lozinski]

[Dave Haynie] “A couple of problems occur. You’re more sensitive to memory-related slowdowns during rendering, and the rendering algorithms have to everything you see during editing, and then some. So you might think you’re ok with N MB set aside during editing, but you run short during editing.”

Hey Dave:

I guess I don’t understand this at all. Because in my mind if I set my dynamic ram to say 8GB, I still have 8GB left (of which about 3GB is used by Windows). So there shouldn’t be any thrashing per-se.

Also, while watching the task manager during the render, the memory usage never gets close to peaking. So in my mind Vegas should be able to load large clips into memory, and then perform the render.

Having to decrease the amount of dynamic ram to 256MB when I have a machine with 16GB to speed up encoding is completely counter intuitive.

There must be something else going on of which I don’t have any idea at the moment.

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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[Dave Lozinski]

I ran a few tests tonight. I downloaded the latest version of Vegas too (they released version 511).

If I have the memory set to 128mb or 256mb, Vegas zips through the video with GPU accelerated encoding.

If I set any value higher than 256MB, it slows down tremendously.

I do not understand why because I have 16GB of memory in my machine, and the only thing I have up and running besides Windows is Vegas. It seriously is just a 5 minute short video with no effects other than a fade-out.

The other interesting thing is if I increase the amount of dynamic ram for the preview to number like 9000MB, generate a dynamic ram preview (which takes a long time in itself! Go figure?!), and then try to render it takes even longer.

Going to reply to another post in this thread, but I guess the lesson here is if it’s taking too long, for whatever reason try decreasing the amount of dynamic ram!

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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[Dave Lozinski]

Mike,

Yeah, I remember reading something here as well but couldn’t find it.

Anyway, will try your suggestion about the 128MB, see what difference that makes, and let you guys know.

Personally, I have 16GB of ram in my machine so setting the dynamic ram preview amount to 8GB, logically to me, shouldn’t make that much difference!

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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[Dave Lozinski]

[Hayden Roberts] “GPU rendering with Mainconcept AVC with my GTX 580 was 520% (equivalent to 5.2x) faster than using just my Intel i7 2600K (overclocked to 4.7 GHz too)! That is an insane improvement. Sony AVC was only a 18% boost using all the same settings.”

Curiously now… have to ask why the Mainconcept would be so much quicker than the Sony one?

Surely Sony would have optimized the code for theirs? 🙂

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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[Dave Lozinski]

Says “video is private” so can’t view it to provide you with feedback.

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[Dave Lozinski]

Have you tried right-clicking on the photo event in the time line, selecting properties, and then seeing of the box is ticked that says to maintain aspect ratio or not?

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https://www.davelozinski.com
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[Dave Lozinski]

You won’t really see much of a difference unless the transitions/effects you’re using are GPU accelerated.

Also, you need to check in Vegas that GPU acceleration is activated. Go under options and under the video tab there should be a dropdown which allows you to select gpu or cpu. Make sure it’s set to GPU.

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https://www.davelozinski.com
https://www.davelozinski.com/DemoReel/
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