That is not the case with Davinci resolve studio. The preview works perfectly. I hope there is a fix for Vegas pro.

Dynamic ram preview at 0MB hurts performance- put it back on the defaults.

What version of VEGAS is this? In VP 21 HEVC support is improving, especially as you are using NVDEC for decoding (I assume, check file io in preferences). In build 187 try with experimental HEVC decoding on and off and see if there's any improvement.

Not all HEVC is the same, either. Some is not able to be decoded by an NVIDIA GPU. What is your HEVC? Use MediaInfo to answer: https://www.vegascreativesoftware.info/us/forum/faq-how-to-post-mediainfo-and-vegas-pro-file-properties--104561/

Personally I'd use your fast CPU to make proxy files (right-click the media and "create video proxy."

That is not the case with Davinci resolve studio.

He needs to fix his computer, Like RogerS said, are you using VP21b187 and if so what decoder is in use, and post mediainfo for your file.

If it's using the new Vegas HEVC GPU decoder I would expect it to play fine on any half decent hardware. I did notice it won't play 6K smoothly with new decoder on Best/FULL, however it does play smoothly at Best/half which is a really good compromise

A couple of things...first, upgrade to build 187. The screen capture you provided appears to be 108. Second, please give a MediaInfo readout on the hevc media you are using to help us diagnose the problems you are seeing with preview performance.

I am currently using Vegas Pro 20 Build 411

Which type of HEVC is it? Please provide Mediainfo: https://www.vegascreativesoftware.info/us/forum/faq-how-to-post-mediainfo-and-vegas-pro-file-properties--104561/

You can try both legacy HEVC decoding and not but don't expect great results with NVDEC. Consider a trial of VP 21 to see if it works better.

If I were you I'd just create proxy files or shoot AVC.

@Bini Resolve is better optimized for Nvidia than Vegas which is more general purpose and better optimized for Amd and Intel graphics than free Resolve. Your setup with no Intel igpu and only an Nvidia Quadro may be great for Resolve but not so much with Vegas. If you dropped an Intel Arc in as a 2nd gpu, even a dirt-cheap a380, that would boost your Vegas hevc performance with vp20. Personally, I'd do that 1st. But if you did a vp21 upgrade too, performance would be even higher. And if you're running Resolve Studio, having an Intel for decoding would benefit that too.

I just downloaded VP 21 TRIAL and the results are the same...

@Bini
Try again after unchecking Legacy Decoder in File I/O and setting RAM Preview Max at Video to the default value

@Bini Try it on Good or Best (Half) as @Former user suggested, that's the preview I use the most, & Legacy HEVC off as @j-v mentioned.

What are your settings in preferences file i​​​​​​o​​​​​​?

At the moment NVidia has turned of some GPU features when running VEGAS in their professional line of GPUs, so it is likely that is also contributing to the sluggish behavior you see.

@rogerS

Here is the file, please let me know if your pc is lagging.

http://www.mediafire.com/file/per4m390omvncrq/IMG_1305.MOV

@Bini
Your file plays well on laptop from signature with all settings default in Vegas 20 latest build and Vegas 21 latest build. look

Thats very interesting. I believe my pc should be able to handle this file. 🤔🤔🤔

@j-v this must be the issue...

Very strange...I tested this out on several machines with many difference GPUs, including one with an older Quadro card, but I get 60fps while playing back.

@Bini I don't think I've had a 60p vid play so well before. (Best (Full) was the same)

So my experience with this is 1-3fps with the 1080Ti GPU enabled (basically no GPU decode). If I use the iGPU Intel UHD 770 (CPU graphics) I get 60fps at Best Full. This is with V20.411 My GPU is about 10% slower than the P6000. My GPU can decode H265 8bit, 10bit and 12 bit 4:2:0 but V20 is not using it to do so. When importing it into V20 I get a message that V20 is downloading the mainconcept HEVC decoder. Looking at the decoder being used it is so4compoundplug.dll for both UHD 770 and 1080ti so the V20 so4compoundplug only uses the 770 for hardware decoding this file.

@Bini does task manager show the P6000 as decoding the video?

@andyrpsmith @VEGASDerek Apparently the problem is with Xeon CPU. They do not decode and encode HEVC files

Yes but what about the P6000 when selected in hardware decoder to use in File I/O tab? I suspect no as it is similar to my 1080Ti.

That makes sense as the legacy HEVC decoder in VEGAS Pro 20 only uses the CPU. You can try to turn off the legacy HEVC encoder and see what success you have with that file.