Yes, it can. However there are many types of 4K 60fps footage. Which is yours specifically? https://www.vegascreativesoftware.info/us/forum/faq-how-to-post-mediainfo-and-vegas-pro-file-properties--104561/

What hardware are you using- CPU and GPU model?

Format                          HEVC
FormatInfo                     High Efficiency Video Coding
Format profile                  Main 10@L5.1@High
HDR format                      SMPTE ST 2086, HDR10 compatible
Codec ID                        hvc1
Codec IDInfo                   High Efficiency Video Coding
Width                           3 840 pixels
Height                          2 160 pixels
Display aspect ratio            169
Frame rate mode                 Variable
Frame rate                      59.940 (599401000) FPS
Minimum frame rate              58.824 FPS
Maximum frame rate              62.500 FPS
Original frame rate             59.940 (600001001) FPS
Color space                     YUV
Chroma subsampling              420 (Type 2)
Bit depth                       10 bits
Bits(PixelFrame)              0.118
Stream size                     65.7 MiB (100%)
Source stream size              65.7 MiB (100%)
Color range                     Limited
Color primaries                 BT.2020
Transfer characteristics        PQ
Matrix coefficients             BT.2020 non-constant
Mastering display color primar  Display P3
Mastering display luminance     min 0.0000 cdm2, max 1000 cdm2
Maximum Content Light Level     1000 cdm2
Maximum Frame-Average Light Le  1000 cdm2
mdhd_Duration                   9459
Codec configuration box         hvcC

2. ryzen 3950x, nvidia 2080ti,/ i913900k, rtx 4090

3. hdr:on, 32-bit full range, aces version 1.2 / color space default,

You have some issues here:

1. HEVC is hard to encode anyway

2. the framerate indicates that you are shooting with a handset. Nice, but seems to generate a fluctuating frame rate, what is extra hard for any software

3. it is correct to apply an ACES transformation for this correct, but that is even more calculation intensive

4. the ryzen is a 16 core processor. But the bad news are, that it does not have an i-GPU (and for HEVC the i-GPUs are typically very helpfull for decoding)

5. the  i913900k has an i-GPU, so here your footage should run much better.

If you use ACES for that, be prepared to reduce the preview quality in a significant way (maybe to preview/half or preview/quater). For HDR projects, it is no solution to run proxies in Vegas, due to color space issues. So one possible solution could be to convert the footage to another format that shows a better playback behavior (e.g ProRes, AVC). A third solution could be to edit the footage using LUTs in the color grading portal - and to run the project as 8bit project for editing - and switch to 32bit for rendering (but without ACES then if you continue with the LUT). Or to apply the LUT on the output level for the cutting process only, work in 8bit - and delete the LUT and switch to ACES for the color grading only.

It would also be helpful to know what is your target format - so is it rec709 or is it HDR?

I'd do the edit in an 8-bit non-HDR mode and then turn on ACES for color correction as you don't need fluid playback for that.

10-bit HEVC 60fps in 32-bit ACES mode is very challenging for VEGAS to handle in real-time.

I do the same as @RogerS describes. My footage are 10bit422 ProRes/longGOP-AVC movs.
4k60p project. Preview Good/Half -> fullspeed playback:

Can Vegas 20 preview 4k hdr footage at 60fps?

I'm trying to edit a video but the preview is 1-2 fps on a windows 10 high end pc.

Depends on the camera file/codec, for Vegas that could be correct. I found with Iphone HDR footage Vegas render engine is 8x slower than it's competition in playback, while with rec 709 AVC it's only 2x slower. It shows the poor abilities of Vegas HEVC 10bit playback.

I have began experimenting with scene detect as a benchmark, and so far seems quite accurate to determine if Vegas is able to playback a file in real time. As an example. cut down a camera file to 60 seconds, run Scene detect, if it completes in 60 seconds or faster you should playback no problem, but if it is slower you will have a problem.

This is a comparison I made with Capcut using scene detect, it is flawed though because I am comparing scene detect with a 1;32m iphone file on capcut with a 1;05m file on Vegas, I had accidentally cut the iphone file on Vegas timeline.

The first file is IPhone HDR 10bit HEVC, the second file is Vegas created rec709 AVC from the Iphone footage, you can see Vegas will complete scene detect on the rec709 AVC at a much more acceptable rate and see Vegas splitting the file at black frames, where as Capcut see's no black frames on the original iphone footage. That's another Vegas flaw but not relevant here.

I made this for a black frame thread, but never posted due to the error and never bothered fixing it I think it's useful for this thread. Playback is at 4X

Edit your project in 8-bit mode, using proxies if you have to, and then when you go to color it, set your preview quality to best (full), switch your preview settings to 32-bit HDR mode, enable your color space transforms in the properties of your media clips to the proper color space... And then color your video. You don't need smooth preview to color the video, so you can get your editing done in lower quality modes and then do the coloring afterwards. Then render to HDR from there.

Cheap to try:

Good to make sure your Media Properties are correct:

Typically you'd want full range, not limited, for HDR, and most HDR is mastered at 1000 nits, not 2000... As few HDR TVs get above 1k.

It was an example. Any similarity to the poster's footage, which is also Limited Range, is purely coincidental. The 2000 nit example footage was downloaded from Youtube, I understand it's fairly common there.

Maybe they've fixed the slow HEVC 10 bit in Vegs in the new VP21 and these work arounds may be unnecessary , @jetdv thoughts?

I think we lost the OP we're trying to help. Maybe if wedge comes back we can keep going.

I'm still here. I just gave up on it. Vegas has a hard time with my video. All the comments was helpful.

My ryzen didn't stand a chance even in 8-bit mode on any preview resolution. I had to use video proxies. i9 13900k was similair. However, changing the framerate properties to 29.97 made the video play back smoothly. I'll try again in a few years.

@wedge can we test my idea about using scene detect to judge how well Vegas handles your playback.

Cut file down to 60 seconds, right click on your file in the timeline select 'Detect Scenes and Split'

As an example for that Iphone footage I was testing it takes 1m20s to process, and it plays on my computer at 40fps, rather than 60fps. If it did process in 1minute or faster I would expect it to playback at 60fps.

What might cause confusion is when Vegas starts out playing at 60fps, but reduces later on in timeline or after an edit point. Vegas builds temporary caches to help with smooth playback, but if it can't decode your file at 60fps it will end up being a laggy experience

4m:12s.