More accuracy and improved models should require more CPU juice, that's a given.

True that.. about time I get a newer computer for this particular set up anyway and faster interface.

Try a slight increase in the the audio buffer size under devices. Try increasing it until the problem disappears.

I made sure everything that could affect performance (e.g. Spotlight) was not running, but it didn't work.
It couldn't even handle 10 voices.

Now I tested 6.5.3, but it didn't look great either.
The "Audio load" graph under the CPU tab of the settings gets filled with red dots and lines; this does not happen on 6.4.1, where I can do a full-range glissando without a glitch.

I haven't used 6.5.0 and 6.5.1, but I suspect it's Pianoteq 6.5.x's problem.
Maybe the thing about CPU requirements in the version history is related.

I guess I have to keep using 6.4.1 on old Macs.

[Edit: I see there are already a number of posts about 6.5's performance in other threads. Looks like 6.4.1 is indeed the only way for me.]

You can just change the version number in the link...

https://www.pianoteq.com/download?file=...p_v650.exe

For example.

Says I am not allowed to access ... At least Pianoteq 5 is playable for now on my laptop... I'll look into a newer computer soon if I have to

https://www.pianoteq.com/download?file=...p_v650.exe

For example.

Wait, the SAME version worked fine a few days ago, or you did an update of Pianoteq and then you noticed the change in performance? This wasn't exactly clear from the first post, so sorry for jumping to conclusions.

It worked fine the other day with most recent upgrade so no version change... I’ll try the finder disable later...