Yes, it is more data, but it feels like not a gradual decrease, but a brutal drop in performance. Regarding rendering why it makes a different is that if I say have a 5min clip with maybe 10 transitions, then rendering this clip the rendering will basically come to a halt 10 times, instead of just blazing through like with 2.7k.... .. but yes, it works, I can go grab lunch or something ;)

I was just surprise of the huge difference. I would have expected a say 25% decrease from 1080p -> 2.7k and then again 50-75% decrease from 2.7k - 4k, but now I see basically no decrease 1080p -> 2.7k and about 99% decrease 2.7k - 4k.

It's also comes to halt in preview, but I can live with that... and I go for lunch during render, but just saying, 2.7k super fast, 4k super slow.. and I cannot see why we see no linearity from 1080p... it's like there is an invisible cliff after 2.7k where all communication just stops in the computer ;)

Post mediainfo for the two types of clips, 2.7 and 4k. I'll bet you $1 the codec is contributing to the slowdown.

Also, have you tried using a format intended for editing, such as prores?

Perhaps share a screenshot of your render settings. Does the media, project and render framerate match?

What is the source media? DJI or GoPro?

Are you using the NVIDIA Studio driver?

Will share, on laptop now, but later today. Thanks for showing interest :)

When footage is GoPro than 4k is HEVC and 2k7 is AVC.

Ok, so I did the following test.

Not super exact, but difference is so huge so I think it's ok.

I filmed three clips, 10seconds each with a GoPro Hero 9

10secs 1080p

10secs 2.7k

10secs 4k

Then I cut a second between 2-3secs and 6-7secs in each clip and merged these with a 0.2sec transition. I.e each clip became shorter by approx 2secs and had 2*20sec transition.

Project settings I let Vegas set to 'first clip added to timeline'

Results rending time (attaching screenshots also)

1080p: 7secs, 43fps avg

2.7k: 8secs 41fps avg

4k: 1min 23sec 4fps avg

NOTE! I'm rendering to 1080p

4K has four times as many pixels as 1080p.

But your processor is not running four times faster. In fact, it probably hit a plateau between the 2.7K and the 4K loads.

Numbers look entirely reasonable (and fast) to me. What about them is bothering you?

Can you upload a sample of the 4K clip to the cloud?

@8500rpm
Are in your test all the same projectsettings or is the 4K file played and rendered in a 4K project to a FHD file?
And mind this

4K has four times as many pixels as 1080p.

But your processor is not running four times faster. In fact, it probably hit a plateau between the 2.7K and the 4K loads.

Numbers look entirely reasonable (and fast) to me. What about them is bothering you?

I agree Mr Musicvid, I am also looking for the plateau if it's not a bug, since there must be a plateau as the difference between 1080p and 2.7k is pretty much non existent. Somewhere between 2.7 and 4k there must be a wall... the thing is, computers won't become 2x faster in 2years, which mean, rendering 4k will still 2years from now according to my tests be way way way way slower than 2.7k :(

AND, yes, I am super happy with my (FAST) numbers in 1080p and 2.7k...

@8500rpm
Are in your test all the same projectsettings or is the 4K file played and rendered in a 4K project to a FHD file?
And mind this

I'm starting Vegas over for each test... and after import of clip I let Vegas set 'projects settings to according to first clip' or whatever it asks when dragging the first clip to timeline. So thereafter the projects settings should be as original clip.

Can you upload a sample of the 4K clip to the cloud?

I can upload another clip, with same camera, which is more 'anonymous' :) (to the cloud), what do you mean, this forum or a dropbox share or similar?

I'm starting Vegas over for each test... and after import of clip I let Vegas set 'projects settings to according to first clip' or whatever it asks when dragging the first clip to timeline. So thereafter the projects settings should be as original clip.

So try, if your goal is FHD (1920x1080 pixels), to start the project with that projectsetting, because it is not needed and costs very much more processing with a higher setting than needed.

rendering 4k will still 2years from now according to my tests be way way way way slower than 2.7k 

All else being equal, that is a reasonable statement. Welcome to the forums.