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xberk wrote on 6/25/2009, 4:43 PM
Read this thread -- it has some good explanation about Dynamic Ram Preview settings (you'll learn what it does and what its for) and good ideas to help smooth out previews.. V9 Choppy previews discussed.

Paul B .. PCI Express Video Card: EVGA VCX 10G-P5-3885-KL GeForce RTX 3080 XC3 ULTRA ,,  Intel Core i9-11900K Desktop Processor ,,  MSI Z590-A PRO Desktop Motherboard LGA-1200 ,, 64GB (2X32GB) XPG GAMMIX D45 DDR4 3200MHz 288-Pin SDRAM PC4-25600 Memory .. Seasonic Power Supply SSR-1000FX Focus Plus 1000W ,, Arctic Liquid Freezer II – 360MM .. Fractal Design case ,, Samsung Solid State Drive MZ-V8P1T0B/AM 980 PRO 1TB PCI Express 4 NVMe M.2 ,, Wundiws 10 .. Vegas Pro 19 Edit

rmack350 wrote on 6/25/2009, 11:47 PM
Vegas does a couple of things with preview RAM but all of it boils down to caching uncompressed frames in memory. When you play something, anything, everything, Vegas must decompress it and it saves those uncompressed frames in RAM, throwing out old cached frames as new ones are loaded into RAM.

You can explicitly tell Vegas to do a RAM prerender and it'll load all the cached frames it possibly can into your preview RAM. Vegas also just loads frames into RAM as you go and this speeds up subsequent plays.

Unfortunately, Vegas doesn't "read ahead" in order to try to give you better playback the first time you play, so your preview RAM setting can have only a very limited effect on your playback.

How much preview RAM you allocate is up to you but there are practical upper and lower limits. Zero preview RAM can hurt while 16MB can be enough sometimes. You always need a little.

If your preview RAM setting is too high it can starve your system for memory. Remember that Windows also needs RAM. If your setting is so high that it forces something (it doesn't even have to be Vegas) to be shunted off to the page file then you're creating unnecessary disk activity. If your preview RAM is WAY, WAY too high then you could force a system to constantly thrash the page file as it puts away and then retrieves needed parts of Vegas or the OS.

On the other hand, if you're in the habit of using RAM renders then a high setting can help you out by allowing you to render more of the timeline. Ideally, you want to use a 64-bit version of Windows with 4 or more GB of RAM. This gets you past the ~3GB limit of a 32-bit OS and gives you a little more RAM for both Vegas and the OS. Even 32-bit Vegas benefits from a 64-bit OS loaded with lots of RAM because it doesn't have to compete with the OS for that RAM.

So the basic answer is "Not too low and not too high". Generally, the preview RAM setting doesn't help playback all that much but setting it too high or too low can hurt playback.

Rob Mack
erikd wrote on 6/26/2009, 1:05 AM
I have dual quad core, 8gb ram, 32bit XPPro. Mack what is high for my Vegas 8 setup? You talk about low and high but these aren't super helpful. I currently run mine at the maximum of 1024mb. I guess that makes me very high. :-0
John_Cline wrote on 6/26/2009, 2:47 AM
If you're running 8GB under WinXP then about 4.75 GB of your RAM is completely invisible and unusable to the OS or any programs. WindowsXP will only see and use about 3.25 GB of RAM regardless of how much is installed. Also, 32bit Windows programs can only use a maximum of 2GB of RAM each. Setting your preview RAM to 1024 under WinXP is NOT a good idea. I'd suggest maybe 512 MAX.

If you have a dual-quad core and 8GB of RAM, you really need to be using a 64bit OS like Vista64 or the upcoming Windows 7 64bit. That will allow you to use the entire 8GB of RAM, although any 32bit programs will still be limited to 2GB each. 64bit programs, like the the 64bit version of Vegas v9, will use all the available RAM as you've got. (Minus, of course, what the OS needs for itself.)
erikd wrote on 6/26/2009, 3:21 AM
John, thanks for helping out. I bought this computer as part of a Matrox Axio Premier CS3 box with the idea that when CS4 came out I would switch over to a 64bit OS at that time.

That was before I decided to do my editing work in Vegas. Vegas changed everything but I still need the Axio hardware for capturing various video sources and for professional print to tape options which I find lacking in Vegas since it doesn't have hardware support for playback.

That said, I am waiting to go to 64bit Vegas as I hear there are lots of issues with switching over to 64bit such as apps only work with 32bit, fx filter, etc. I really want to switch over to 64bit when everything works smoothly in that world. I don't want to work half in 32bit and half in 64bit.

It sure would be nice to get the 8gb of ram working for me but I don't think it outweighs the issues of switching to a 64bit environment. I think when the time comes though it will be the upcoming Windows7 and not Vista which is another reason for me to wait things out awhile.

Does this make sense to you?

Erik

erikd wrote on 6/26/2009, 3:22 AM
John, one more thing. Why do suggest 512MAX? I haven't noticed any problems with 1024 so I would like to know more about what you are describing.

Erik
blink3times wrote on 6/26/2009, 3:51 AM
Anything higher (for some reason) tends to slow renders down a bit. I keep mine as high as I need during editing (sometimes up to a gig or more... and I use SHIFT-B quite heavily for avchd editing) then bring it back to 256 on render.