Yes, everything is fine, latest studio driver. Vegas Pro sees it in Preferences | File I/O, but in Preferences | Video "GPU acceleration of video processing" it shows "Off" with no other option.

If you replaced that card while Vegas 18 already was installed you have to reset Vegas 18 exactly following this tutorial ( also deleting cashed data): https://www.vegascreativesoftware.info/us/forum/faq-how-can-i-reset-vegas-pro-to-default-settings--104646/

Everything is not fine if it's not found under preferences/ video.

Agree with J-V to start with a reset.

If there is also an integrated GPU, under "graphics settings" (Windows) you can assign VEGAS to the high performance GPU.

I was hoping to avoid resetting Vegas, but if that will fix things, so be it.

Instead of resetting VP 18, I installed a fresh copy of VP 19. The problem remains -- Preferences | Video "GPU acceleration of video processing" shows "Off" with no other option. It's the only display adapter in Device Manager, Windows sees it in Display options, Vegas shows it in Preferences | File I/O.

It doesn't even show the internal graphics processor -- Intel® HD Graphics 530.

Try setting graphics settings to your main GPU and resetting 19 then.

Where are these versions of VEGAS coming from?

I'm not sure what you mean " setting graphics settings to your main GPU". Vegas software is coming from Vegas site (vegascreativesoftware). VP 18 is standalone and VP 19 &20 from Vegas Post.

It's what I wrote above. Type "Graphics Settings" in your Windows search bar. Your main GPU is "GTX 1660 Super". Selecting "high performance" there should assign it for use with VEGAS.

I submitted a Help request to the publisher, but from past experience their response will not be quick.

So you didn't check graphics settings or reset VEGAS.

What errors did VEGAS have with the GPU? You can see what it finds here for your GPUs.
C:\Users\Username\AppData\Local\VEGAS Pro\19.0\ gpu_video_x64.log

I didn't check the settings YET, because the client has not answered my calls, apparently is working in Vegas Pro (I only have remote control software to do so) and this change will require a restart. He is one of those clients I will have till the day I die -- I'm sure most of you know what's like. He's a "forever" client.

I reset the settings from Off to On. No difference in Vegas. I tried in VP 19 as well with no change. I reinstalled the nvdia drivers using a clean install. No change.

The user reports there is an improvement in rendering speed compared to his previous video card, so he's pretty happy. I would like to find the problem because there's no telling when this might be a problem in the future.

Sorry, you're confusing me. The first message says "I" but now you are working on behalf of someone else?

What does resetting from off to on mean?
Resetting VEGAS means holding control + shift while starting the program from the desktop or program icon. Turning the NVIDIA GPU on in preferences/ video will make a difference in VEGAS-- if it works. If it doesn't work the log has info about what failed that may give you a clue.

For rendering speed that's fine but I thought the issue is no NVIDIA usable in "Video | GPU Acceleration of video processing." That will significantly harm preview performance and I agree should be solved.

I am starting to think there is an issue with the change of GPUs and Windows. I would use DDU uninstaller to delete all traces of drivers from the old card and then try the new one again. This helped me in the past.

Let me clarify.

The issue IS "no NVIDIA usable in "Video | GPU Acceleration of video processing." It should be solved. The user noticed an improvement in rendering speed even though the problem exists, so he's temporarily happy and I can continue troubleshooting the problem.

You asked me to check the graphics settings in Windows. The setting was Off so I reset it to On. No change to Vegas.

I know what resetting Vegas is, but I was reluctant to do so since it would interrupt a working system. I therefore chose to install a clean copy of Vegas 19 to see if that version suffered from the same problem. It does.

I'll try DDU the next chance I get. Thanks for tip.

For graphics settings in Windows I don't see off as a choice (Windows 10 shown here).

I first selected my version of VEGAS (browse) and then here are my choices.

For hardware-accelerated GPU scheduling I have it set to off on this older system.

Good luck with DDU- given the fresh install of 19 that's my guess as to where the issue lies.

Yes, but that's Graphics preferences, after you select an app. The previous menu, Graphics settings, has a slider for On and Off.

I don't know how you got the image in your reply -- copy and paste doesn't work for me.

I don't know how you got the image in your reply

Please see e.g. this comment.

@hurricane1951

If Graphics Settings is hardware scheduling off is probably fine (you can search for hardware scheduling and what it does and not).

Graphics performance preferences under graphics settings can help VEGAS find GPUs but probably won't work.

I saved the screenshot to my computer and then uploaded it with the button next to the smiley face.