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Fine-tuning RAM/Core settings
Hi all,
I spotted some threads about setting maximum amounts of RAM preview on the Forums, so I decided to have a go. FYI: I’m using Windows 7 (x64) with a Core i7 (860) based machine, 8 GB RAM.
When I first got this I thought I’d give it a good spanking and let it use 7GB of the RAM and the option to use all 16 of its hyper-threaded cores. Results have been erratic. Occasionally rendered (particularly .wmv) video is faulty and on a few occasions the machine has hung or crashed without providing a useful dump file.
Here’s the interesting thing though: Putting the RAM settings down to 5000 MB seems to massively increase the rendering speed – literally half the time taken with 7000 MB.
This suggests that there’s some sort of sweet-spot which it should be possible to calculate rather than work out by trial and error. Anyone know what the equation is for this?
Similarly I’m now wondering if letting the beast have all of the processor cores is such a smart idea – anyone done any tests on this…?
Any input gratefully received.
John Matchett
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5 Replies
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Here’s the interesting thing though: Putting the RAM settings down to 5000 MB seems to massively increase the rendering speed – literally half the time taken with 7000 MB.
If you are referring to the RAM Preview setting this makes perfect sense. RAM preview has nothing to do with rendering other than to steal memory from it. It only works for preview and determines how much memory is set aside for using the RAM preview function. In effect, it steals memory that would otherwise be available for rendering.
It makes perfect sense then, that setting the RAM preview to 5GB from 7GB would increase rendering speed because you just gave Vegas MORE memory (2GB more) to use for rendering. I’m surprised it rendered at all set to 7GB (which left almost no RAM for rendering)
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thanks for the reply John. That’s interesting, and I wouldn’t have guessed. I’ve been doing this wrong for ages. I was very enthusiastic about finally getting access to all that RAM on a 64 bit machine, but it looks like I’ve actually been making it worse!
Whilst I fully understand what the RAM preview is doing – and find it very helpful on complex HD projects – it’s less-than-obvious that ‘allowing’ the machine to use a given percentage of the RAM means that it’s unavailable for anything else. Perhaps Sony ought to clarify this within the preferences dialogue as I’m sure I can’t be the only one generously allocating all my precious memory resources.
Any pearls of wisdom about ‘maximum number of rendering threads’? Is it safe to leave this max’d out or should I be throttling this back? I’m never sure how smart PCs are at negotiating the use of their cores.
Thanks again for taking the time to reply.
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Perhaps Sony ought to clarify this within the preferences dialogue as I’m sure I can’t be the only one generously allocating all my precious memory resources.
They do. Didn’t you heed the warning? I just set my RAM preview to 512MB and here is the warning I got from Vegas Pro 9.0c:
That pretty much should tell you that setting too high will have negative effects. I don’t know what else Sony could have done if that didn’t warn you.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
I too have been doing this wrong, one would think that once you start a render that there would be no need to allocate RAM for a dynamic ram preview!! It is quite useful to be able to use the dynamic ram preview to watch transitions and such in real time, since Vegas is choppy with their preview when edit HDV (even with an Intel Quad core). I will adjust as well. THANKS!!
Regards
Scott Francis
Mind’s Eye Audio/Video Studios -
Hi Scott,
I’m glad it’s not just me being an idiot then! If you’re using Vista or Windows 7 you can easily put one of those sad boy-racer CPU gadgets on your desktop – I now have one on my right-hand monitor below the preview pane, but don’t tell anyone!
I’ve tried several settings now and the results are suprisingly different both in terms of how much of the % of the RAM is being used, but especially in terms of how hard the processor cores are working. I’ve now got my CPU peaking at 90-97% which is way better than before (20-25%).
Interestingly (and kind of counter-intuitively to me) setting the ‘Dynamic RAM preview max’ to zero as i’ve seen suggested elswhere, doesn’t seem to give the best results for me. FYI: I currently have mine at 3GB – my machine total is 8GB – and this seems to give a sensible balance.
Either way – like you – I’d assumed that this RAM setting would be over-ridden if I wasn’t actively using the RAM preview (i.e. once the machine was in full rendering mode) and that’s where the confusion was coming from.
John Matchett
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