Under help in Vegas Pro 18 did you try the driver update feature? If you're not on the latest NVIDIA studio drivers, do upgrade and try again.

Also, I'd reset the preferences to defaults in case some settings you had from 17 are carried over and causing issues.

I find preview window performance similar to or slightly better than VP 17.
 

I have been searching, but really can't find anything to help. I have updated the drivers as suggested just now. Still the same situation. If I reset preferences to defaults in 18 will it affect 17? I really can't afford to be blown out of the water. I do several edits a day now for work.

Most of my work is timed to music, and I need to preview smoothness and stability before rendering. I just tried viewing the monitor at a reduced size and reduced quality. No change. I can't see transitions, and I can't tell because of the lag and choppiness if the footage is smooth.

Your CPU, GPU and ram are good. Something else is the problem.

Resetting Vegas Pro 18 won't affect 17 in any way. Turn off legacy decoding, keep File I/O decoding to "auto" for now.

For the preview window, are you at best/full? If so, maybe drop back to preview/full just for playback.

You haven't posted what media you are using. If it's HEVC or other highly compressed formats, consider creating proxy files to speed the preview. That shouldn't be any different with 17, though, so if it works there it's not a media issue. It's not a good sign that the GPU crashed in 17- something is wrong with this system.

Out of curiosity, could you try going through a GPU benchmark (this one is free) and see what kind of framerate you can and if it crashes? https://benchmark.unigine.com/heaven

I had been blaming Vegas for poor GPU performance only to find out my computer bios and thermal management had a serious issue that was leading to GPU instability. The benchmark helped me figure that out.

Thanks. I will try to reset settings to default with fingers crossed. Nothing is crashing. Just slow chopping preview and render is way slower than 17. A 3 minute not very complicated project rendered in about 20 minutes.

You said GPU was crashing in 17- it shouldn't have been, so something is wrong.

Yes it was an issue for 17 initially. The fix was to turn GPU rendering off. A few updates after that, it was resolved.

As a general proposition I wouldn't recommend upgrading to any initial build of a new Vegas version if you're still having system issues with the previous one. Sort your system out first with the older more stable version before you introduce new-build bugs on top of your system issues.

The cpu stress tester I always start with is prime95. If there are thermal, overclocking, voltage, or memory issues it will error out till you fix them. You can monitor cpu thermals with CoreTemp. If p95 runs overnight, you're good for those things. Next I do gpu stressing. I don't know that there's anything for windows quite as elegant as p95 for gpu's that shuts itself off as soon as it detects an incorrect gpu computation so the usual practice is to watch the display output and gpu thermal monitors while they run and stop it manually if necessary. Or hope the gpu stops itself before it gets damaged. 3Dmark is probably the mildest and safest one. Kombustor is a little more aggressive but relatively safe. FurMark I'd be real careful with. Running an array of Vegas project benchmarks is what I do last. If the gpu is just ng... the only solution may be to try a different one. Fwiw, I love Asus for motherboards. But not so much for gpus or its ai software. Speaking of which, if you installed v18 Deep Learning Modules... they may be detecting your system problems and throttling Vegas at times for your own good. Ha, ha, without so much as an, "I'm sorry Dave, but I can not do that."

I know, I try to resist jumping on the upgrade wagon, but I just can't help myself. I must say that 17 is a great companion. I have learnt the (ctrl S) twitch because it will crash now and then with no warning...., and I really didn't want to upgrade and thankfully 17 is still working great. Was up to all hours editing last night. I just upgraded my computer to help with render times and I am glad that I did. Everything works fine with 17. Now I have to find time to play around with the settings for 18 or to wait for the next build.

I'm sorry, but I have been forced to now work with a project in Vegas 18. I so regret upgrading. Please be warned. If you have a stable 17 working for you. PLEASE STICK with it until they have issues ironed out with 18. Its terrible. Horrible even. What a colossal waste of time. Be warned. I will post if I have time how horrible the editing environment is. The rendering is terribly slow. And for the fixes. What a waste of my time. Can't this team put as default the so called fixes? Shameful. I give up, and will go back to 17.

Your results aren't widespread. Here's video proof of 18 rendering and opening projects far faster than 17 ever did... I haven't tested timeline performance yet, I'll do a test with it hopefully later tonight.

I can't tell what I am looking at when I am editing. I wait 20 minutes for a 3 minute video to render to find I have to make changes after the render that I didn't detect because i could not see a smooth transition. I hope these guys read this and start cracking on a better version. Thanks for confirming my thoughts.

do a media info of the video that is smooth on vp17 but lags on vp18

If others with your system specs or lower have no problem, it could be something you can fix