There is nothing mysterious here - you answered yourself with all of the above - so you got that right after all.

Let's assume you have a medium built PC with fast enough card and harddrive handling for multistreams concurrent.
Then what is what? ALL DEPENDS
1) What is your source format codec? what container, what bitrate, what filesize, how have you made subclips out of one event piece and how many subclips, then how many discrete events per timeline track, how many concurrent tracks????
2) Now FX processing - complex multi-layered or chained?
3) How much runtime length given in a single project?

Most all of this is very solved by using appropriate digital intermediates - how you do that ALL DEPENDs - aha, you guessed it - refer to above.

Vegas will vary frame rate to maintain a given image quality, on the other hand, Premiere varies the image quality to maintain a given frame rate. There are advantages to both approaches, perhaps it would be nice to be able to choose one or the other at will.

Thanks, so with my processor I should avoid having more than 4 tracks for optimum playback quality?

Kit

yes but only if you are doing picture in picture or compositing. I have always several tracks but only one is playing at a time or transitioning to another. I did a project in HD 1080 60p with the screen tiled 4x4=16 picture in picture tracks. From that project I noticed that once I added more then 6 tracks things started to become slower until very slow; I run a 3930K which is a 6core CPU.

OldSmoke, could you elaborate on exactly how the change to the R89 290 improved your payback? Given that the 580 is a few years old if I'm not mistaken, are they noticably faster by architecture or simply because they are newer, faster cards?
Also, how exactly do you make use of two simultanous cards - one for preview only and the other for the work screen?

Thanks!

I don't know which variable makes most difference Kit, but I'm currently editing a 6 camera multicam project with the same CPU and getting full fps at Best Quality, and the footage is a mixture of 1 x EX1 MXF at 1920 x 1080, 2 x HDV at 1440 x 1080 , these three cams at 50i, and then 3 Sony Action Cams shooting at 1920 x 1080 but 30fps.

Spec:
CPU i7 3770 @ 3.50 Ghz
GPU: GTX 670 (Drivers 9.18.13,4411)
Ram 16 Gb

Edit - Just looked at another variable. With GPU acceleration turned OFF, playback with 6 cams went from 25 to 18 fps.

Peter

Multicam isnt the same as compositing or picture in picture. In multicam you still only playback one stream at a time. In compositing you are playing back at least two streams at the same time.

The reason the R9 290 is faster is the better implementation of OpenCL in the ATI/AMD cards; Nvidia cards are more focused on CUDA. OPenCL is what is used for playback, there is no CUDA involved in playback at all.
Also the R9 290 has 4GB, PCIe 3.0 and I think evena bigger memory bandwith, 512 vs 384 on the GTX580.

One thing you have to be aware when switching to ATI/AMD: MC AVC and Sony AVC do not support the later GPUs of the ATI/AMD cards, I think it end at the 7xxx series. So even if you select within the MC AVC render template to use OpenCL it doesnt work and it will run on CPU only.

Another plus point is that many 3rd party plugins are OpenCL based and you will see great improvments for things like NewBlue and Boris FX porducts.

I have a 4 monitor setup, 3 1920x1080 computer monitors and one 42" LCD HDTV for preview. I have balanced the load between the two cards by using only ports on each. If you want to use 2 crads, make sure your system does actually support 2x PCIe x16, only socket 1366 and 2011 can do that.

Thanks for the infos OldSmoke.

How to have it set to best full and not have jerky playback? . What makes the biggest difference? Your actual question is actually more about video playback speed (i.e., sustaining full frame speed during playback) than it is about quality (spatial quality, with the full sharpness of the original).

Here's a link to some advice I have given on many previous occasions (this question has been asked before):

Four rules for fast preview speed

Also, if you search, you will find several dozen threads with additional advice.

Here are links to other threads where I gave this same advice. I am providing these in order to give you links to other threads where people were having the same, or similar problem:

Vegas Pro 10: 720p=ok, 1080p=Choke

vegas preview quality - still not getting it

Please critique my AVCHD-to-DVD production. :-)

Found One Cause of Slow Playback Speed

MultiCamera HELP - 6 Tracks of Jerky Video

OT: laptop speed

Kit, I've never tried this, but depending on what your title sequences consist of you might be able to get the speedup you need by using proxies for your media. Vegas 12 and newer has proxy support built in, and there are 3rd-party tools like Vegasaur that can add it too.

Others who have tried it may provide better insight into whether this is worth trying.

/jerry

I refer to my earlier post above...and while I mention appropriate digital intermediates as the cure for 90% of the ailments brought up by the OP...I did neglect the topic of proxies. Indeed if the problem is in the source codec/container type and number of subclips split out of events plus total number of events - then the issue goes directly to proxie usage.

However, this may put you in a real workflow bind if you are doing multiple concurrent tracks in a complex composite - then the DI is the bigger answer.

+1 to intermediates and proxies.These are by far the best way to get great timeline performance. Proxies will give you the smoothest playback, but you will of course lose spatial quality while you are editing.

OldSmoke - I may have misunderstood the OP's question, but surely when I'm looking at six cameras at the same time, Vegas is playing them all back simultaneously.

Yes you do but at a reduced resolution for each of them.

Thanks , Johnny, for taking the time to put together the links. My question is about how to get both full frame speed and spatial quality - that's what I meant by "best full and not have jerky playback" - but I lacked the terminology.

From what I've read following your links I tried setting the deinterlace method to interpolated. You suggested unchecking it but I need to keep Scale Video to fit preview window as otherwise I can only see a fraction of the video. I also checked adjust size and quality for optimal playback. Results are a little better but still not as smooth as I really need.

I'm wondering now about using proxies but don't know anything about what it entails. It doesn't help that help keeps crashing Vegas. Thanks again.

Thanks, what do you mean by DI? Is making a proxie the same as rendering to a new track? Sorry, I'm still getting to grips with terminology.

Thanks, what do you mean by DI? Is making a proxie the same as rendering to a new track?"DI" is a Digital Intermediate, or just "intermediate."

Proxy and Intermediate are two very similar ways to improve the editing experience, especially the preview performance. In both cases, you create a new video file from each and every source video file that you want to edit. This, of course, takes time to do, and consumes additional disk space. You then edit with these new files instead of the original video files from your camera.

Intermediate files have the identical properties to your original video file: they are the same resolution, same frame rate, and virtually the identical quality (the quality differences should be imperceptible to most people). However, each frame is compressed without reference to any of the previous or future frames. This is quite different from MPEG-2, HDV, AVCHD, and most other camera video formats. All of these use a compression technique which requires referencing as many as a few dozen adjacent frames in order to display each and every frame. It takes time for the video editing program (i.e., Vegas) to open all these additional frames and compute what the pixels should look like for the current frame.

The downside of intermediate video formats is that because each frame is compressed all by itself, the size of the video file is much, much larger, usually by a factor of five to ten. For instance, Cineform is a good intermediate codec. 1920x1080 video encoded using Cineform consumes between 58 and 86 GB per hour, depending on the quality settings you choose. By comparison, the AVCHD that your video camera creates probably only consumes about 8-10 GB per hour.

A proxy video file sounds like the same thing as an intermediate file, but the key difference is that it is created at a much lower resolution and quality. The file size is much smaller than an intermediate, and usually smaller than even the original video file. Because it too compresses each frame without reference to adjacent frames, it is also much faster when previewing on the timeline, and because it uses much lower resolution than the original video file, it is even faster on the timeline than an intermediate.

When you edit using a proxy, that proxy must be replaced with the original video files, just prior to rendering. There are lots of scripts that handle this for you automatically if you are using older versions of Vegas, but the current Vegas version supports proxy editing directly (i.e., it will do the replacement for you, just prior to rendering).

So, which to use, intermediate or proxy?

In general, use an intermediate when disk space is not a problem, and when you want the simplest workflow. Use proxy files if you have a lesser computer that can't give you a fast preview, even when using an intermediate. Also use a proxy instead of an intermediate if you don't have much disk space. Finally, even with a fast computer, if you add a lot of effects or apply other advanced editing to your video, you may find that preview speed becomes a problem, even with an intermediate. This is another reason why you might want to try proxy editing.

for some reason I get better playback with all intra AVCHD files (.mts container) than I do ProRes or DNxHD files.... so much for intermediates.....

for some reason I get better playback with all intra AVCHD files (.mts container) than I do ProRes or DNxHD files.... so much for intermediates.....That is a little unusual, but I have seen this on computers with relatively slow disk drives.

Since intermediates are 5-10 times larger, as I explained in my last post, they get large enough that a slow hard drive can become a bottleneck for fast playback. This would definitely be true if you are playing your video from external drives connected via USB 2.0.

There is no exact rule of thumb, and a lot depends on what settings you use to create your intermediate.

Even if your hard drive isn't a bottleneck when you are only reading one stream of video from that drive, it can get to be a problem if you have 3-4 streams of video on separate tracks (e.g., a multi-cam project), and the computer has to read all three streams from large intermediates that are all stored on the same drive.

"[I] ...it can get to be a problem if you have 3-4 streams of video on separate tracks (e.g., a multi-cam project), and the computer has to read all three streams from large intermediates that are all stored on the same drive.[/I]"

See my actual measurements of this scenario in my March 17, 2014 post in this thread.

I remember that thread. Those measurements were useful for illustrating the impact of file size on render speed, but I'm not sure they shed light on this issue because in this thread we're talking about timeline playback performance. However, I'm pretty sure one of us tested playback performance in one of the previous threads on this topic.