Renders with low CPU%

geebjen wrote on 4/9/2010, 9:10 AM
I recently upgraded my PC from a Pentium4 2.8GHz to a AMD Phenom II 820 Quad Core 2.8Ghz machine. One of the primary reasons was to speed up video renders. On my old machine every render would use 100% of the cpu and virtually freeze my PC until it was done.

With the new system I noticed that not anywhere near 100% of the CPU(s) was being used. I did a lot of reading in the forums and did some experimenting and made the following notes:
* MP4's which were low resolution RIPs from DVDs of old camcorder movies used about 85% of all 4 cpu's. That's fine.
* AVI's from my old digital camer also render at around 85% on all 4 cpu's.
* MP4's which are from my Sony H20 camera in widescreen Hi-Def only use about 35% of the 4 cpu's.

Based on what I read in these forums I experimented with changing the output path to a different hard drive, and that didn't make any difference. I also tried changing the temporary files path in Vegas to a different hard drive and that didn't make any difference.

So does anyone have any ideas what my botleneck might be if it's not cpu and it's not disk I/O? Could it be the codec itself, which I think Sony uses the Quicktime one? or something else?

Comments

Chienworks wrote on 4/9/2010, 1:11 PM
Quicktime is notoriously inefficient. I'd point the finger there first. Try transcoding the H20 footage to something else first, like HDV, then try rendering from those.
Eugenia wrote on 4/9/2010, 3:51 PM
Vegas is best optimized for Intel CPUs, as far as I know. So what you're seeing might actually be a not-so-amazing support of the AMD core model.
geebjen wrote on 4/10/2010, 9:06 PM
Thanks guys. I figured it was something to do with the mp4's. I sort of wish the camera used a different format, but it's not the end of the world.