Render speed affected by preview RAM amount (V8b)

Christian de Godzinsky wrote on 3/12/2008, 6:12 AM

I searched the forum and think this subject deserves its own topic:

The preview RAM setting affects dramatically the render speed!!
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This phenomenon is discussed elsewhere in the forums, but in combination with other subjects.

Is this a BUG or a FEATURE ?

Shouldn't this be mentioned in the manual or at least be a part of the top ten "how not to use" Vegas Tips? Other people have also found that the preview ram setting affects dramarically their render times (and CPU utilization). In my last case the render time was improved 3-fold, when the preview RAM was set to at least 128MB, compared to what it took to render with this setting at 0MB!

How consistent is this problem, and which are the common nominators? Has someone already sent a ticket about this to SCS?

I can live with this as long as Vegas brings me to the render finish line every time (as it has always!). However, there is no logic explanation for this erroneous behavior.

How many of you can duplicate this?

Best regards,

Christian

PS: I am running on VP8(b) on a quad core QX9650 and 4GB RAM (and XP x64).

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Comments

Christian de Godzinsky wrote on 3/14/2008, 3:31 AM

Nick,

Didi you also test 0MB ??

Christian

Wolfgang S. wrote on 3/14/2008, 3:39 AM

Sure.

Q6600 2.4 Ghz, 4 GB RAM (but due to some hardware restrictions from the Canopus NX only 2 GB are available, since I run XP SP2 in the 32 bit version).

NickHope wrote on 3/14/2008, 4:26 AM

>> Nick,

0MB 8:23

Christian de Godzinsky wrote on 3/14/2008, 6:50 AM

Nick,

You experience a similar speed decrease (3,2 X ... 3,5 X) than I, when setting the preview ram to zero!!! Other common factors, we both run XP x64 and have 4 GB of RAM and Quad Core processors.

It is now proved (at least with our setups) that setting the preview RAM to zero is not an option, unless it solves any other (like the black frame) problem for you...

I still don't understand how the preview memory buffer size affects the render time? Unless this same buffer is used in conjunction with the render process to speed things up.

Interestingly - the "New Rendertest" re-runs in less than 2 seconds (!!!) - if the preview ram setting is big enough so that the rendered file is smaller than this setting, and if you have not changed the source in any way! This proves that the preview ram really has a some kind of role during the render...

Christian