Hi Hans,
I'm inclined to think that you have a small apples and oranges problem.
First off, I feel that you compare this in Attended Mode (user interface stays). But, not 100% sure. Anyway, when apples and oranges are left out of the equation and Unattended (interface disappears) is in order, a WAV album may start in 6-8 seconds and a FLAC in 2 or so.
How ?
Because the FLAC conversion is performed in parallel for each track (for 12 tracks at the time for your 12 core PC), while WAV "copying" happens per track subsequently.
This latter is the case when any "copying" as such is implied, which may not be your case (with your settings).
Already confused ?
Not necessary - and not even necessary to really understand. The point is : you compare en e.g. 50MB of WAV track with a 30MB of FLAC which needs to expand to 150-300MB. Look :
Your FLAC is say 30MB.
Uncompressed this would be 50MB again *if* it would be 16/44.1 like your WAV. But it isn't 16/44.1, and thus is the 30MB already wrong (it is larger). But never mind, because the math goes like this :
50MB for 16/44.1
This is 100MB for 16/88.2
This is 150MB for 24/88.2
which is 300MB for 24/176.4.
This 150 or 300MB needs to be "written". So apart from the time it takes to do the processing (of uncompressing) it is a sheer 150 or 300MB which needs to be written to disk (the FLAC becomes a WAV).
And your WAV ? 50MB to write only, *if* at all, depending on your settings. So maybe no need to write (= copy) anything (which would be the default for settings).
Summarized :
Your FLAC files are Hires while your WAV's are not.
(this one liner could have been the short answer)
In addition (but already implied) :
If you'd use the on-board RAMDisk and set the Playback Drive to B:\, all will be copied to B: (which would be the RAMDisk) before playback commences. Also WAV. And I assume the "normal" Unattended Playback.
If the FLAC now is 16/44.1, you will see that this copying of all the tracks of a FLAC album takes as long as its longest track (so say 2 seconds) while the copying of the WAV album takes the required time per track subsequently (think 10x 1 second for your comfort).
And so ...
So it is all the other way around as your thought / seem to notice.
Peter