Vegas Pro 15.0 LAG in preview but completely fine in 14.0 (High-End PC)

[MythyMoo]

So I recently got my hands on Vegas Pro 15.0 because I was curios to see the new NV Encode render mode, and to my surprise, I now render x6 times faster than I do with 14.0.

Which is great, worth the investment for what I do, but I have also been struggling with choppy/laggy playback in the preview window. Basically in Vegas 14.0 I can play huge files at 1080p 60fps on Best(Full) and everything works smoothly. But in Vegas 15.0 I will have 60fps (exact same file) in the preview for a solid 5 seconds and suddenly the whole thing just freezes and goes to 13fps instead. The more time I spend in the program, the more lag appears and then suddenly I just can't even preview the video anymore as it literally shows in 1fps

I then go over to Vegas 14.0 again and boom, smooth as a baby's bottom.

PC Specs:
GTX 1080
i7-6800K CPU
32 GB RAM

Files are on a 2 TB drive with over 800 GB available

Things I've already tried:
All sorts of Project Properties (and auto-match)
Dynamic RAM Preview and GPU acceleration (ON/OFF)
TRUE and FALSE on the Internal "Multi Stream Render" option

I just really don't want the money I spent on this to go to waste, and I think that once this is fixed I can truly enjoy the beauty of GPU rendering and the other features.

Any help is appreciated!

 

[zer0c007]

Try using 720p or 480p and see if it works fine, if it does then its a software bug

 

[tystab0403]

I'm having the same exact issue you're not the only one I have no idea how to fix it.

 

[chiltonj]

Same issue with 15.0. Windows 10 64-bit, EVGA Titan X 12GB GPU, 64GB RAM, Rampage Extreme V MOBO, i7 5930 3.5GHz 6 core CPU. When playing (not rendering), preview is choppy and CPU hits around 75% but memory is untouched. I don't get it.