Here is a further description of the downgrading of performance in V23 over V22 related to pan/crop on stills (I first outlined this in the VEGAS Pro 23 build 278 General Discussion).
General observation: v23 renders quite slower than v22 for identical tasks of certain pan/crop parameters of stills. In particular, the slowdown in V23 is much worse for crops that vary over time.
Outline: 1920 X 1080 project using one 4032 X 2268 (24-bit) still @ 5 seconds (from Samsung Galaxy 21). Project properties are the same in V22 & V23: HD 1080-30p (1920x1080, 29.970 fps). Pixel format is 8-bit. No effects are involved in the project. No sound track. A pan/crop is created on the event with a starting keyframe and ending keyframe, then four variations of the ending keyframe:
Starting crop: 2820.8 W X 1586.7 H centered @ 2016.0 X, 1134.0 Y for all variations.
End keyframe variations:
1: end same as start (i.e. no ending keyframe) (fixed crop, not moving)
2: end at 2442.7 X 1394.0 (fixed crop, pan moves down and right)
3: end at same center position as start, size 2394.2 X by 1346.7 Y (crop zoom, no pan)
4: end centered at 2442.7 X 1394.0 size 2394.2 X by 1346.7 Y (crop zoom, pan moves down and right)
Render setting uses the preset: Internet HD 1080P 29.97 fps (Intel QSV). The pan/crop settings were chosen by random hand-edited crops, then reproduced for the variations. This is using my machine with an i5-11400 that has UHD-730.
results in FPS:
V22 V23
-----------------------
1 102.78 65.05
2 72.18 42.92
3 79.10 22.68
4 78.46 22.95
Conclusions: V23 performs significantly worse than v22 with a 4032 X 2268 still in a 1920 X 1080 project. V23 performance dips to less than 1/3 of V22 for pan/crops with changing crop size, significantly worse than real-time.
I haven't done this for videos yet, nor for different render settings. I have noticed related similar performance problems on stills with previewing (on all qualities), and also on my other machine: i7-8700K with UHD 630. I have not checked for the difference in color space handling new to V23.
Conjecture: projects containing events with significant pan/crops will exhibit extreme slowdowns in V23 compared with V22, rendering or previewing.