Wow, you have been busy ...
Let's start with the end : No, everything is 100% from memory, and it always was (each Engine). You may not have expected it, but the "real time processing", is still processing things from memory only. Of course you are not used to it, but since you play without the RAM disk now, look at the disk light ...
There is no single way "playing" from the RAM disk can make a difference. BUT : As you know many other influences play a role, like the spinning disk (or not) and probably the part of memory which is used. So
indirectly you can be right (no, will be right because you say you hear it), but this is unrelated to the "playing" as such from the RAM disk. You might just as well fake the lot by copying another album to the RAM disk than you play from e.g. a memory stick (which may sound different again because of using the memory stick).
The list looks normal to me, yes. On the first couple of tracks and mem useage, keep in mind that physically freeing memory is out of anyone's control in the .NET environment, and that the OS decides when to free the memory. At your 1.3GB it apparently thought "this is enough", and that will have happened at the stage of loading the 6th track. Note that this track temporarily needs more than just that track, like the 30MB it would be on disk, needing 30MB for the file + another 30MB + whatever it took for "processing" after which the first 30MB gets deleted. This takes a few tenths of a sec only, and you won't have noticed it. Of course if the OS doen't throw it away physically, it would add up (like with the first tracks).
I too have 2GB, and it is enough for normal "operation". Indeed Vista takes some 400MB at least, which can easily grow to 800MB "permanently" for the boot session (in my case anyway).
The first time it stopped after the 6th track and gave me the message "Engine #3 did not start within the expected time!".
So far these kind of things have bugged me always, and with all Engines (which are all so totally different that there can't be a relation). Everybody will have this.
BUT :
Is it a coincidence that you mention this for the first time ? I think not. Why ? well, expecially because the only reason I could find throughout time is that this is hdd related. For me it always has been so that "something" happens within the first couple of tracks, which does not happen anymore lateron. And mind you, I'm talking some 500 days = times by now. It's standard. To me it looks like the hdd spins down rather "hard" (and earlier than should) after a first wakeup - after a longer sleep.
I don't know.
There was a fair amount of crackling (static noise) but it was random - only a few songs. But if I stopped and went back and played those tracks individually, then there was no crackling. (It was only when playing the entire playlist)
This is something you can get experienced on (judging it to the real merits) once you first have the "trust" that it's not the program doing it (and I obviously can have that trust). Over time I learned that this is very easy to "see" once you watch the behaviour of the OS closely. An easy one is the OS shutting down a service, which most often goes along with a message saying so. Leave that message be, and you'll get crackling. But now what, when there is no message ? In my case, most often buttons change (and back), but you already have the W3.11 buttons, and they won't change back.
I know, this sounds a little like voodoo (especially to newbies here), but I really can see it coming. But man, there is MUCH more to this;
I am as far that I can "see" on this (behaviour of the OS) how accurate playback is (if accuracy on this matter may emerge from sending out the bytes software wise). Now first look at your own case : you changed from playing (!) from RAM disk to normal hdd and your OS starts to behave differently. Mind you, this can be impeeded by the prio settings (and IMO it should). So, where normally nothing bugged you (or set your settings so it did not), now it suddenly does. Look at the difference between playing 44.1 and 96, where the latter requires more. It may well happen that at the moment you switch to 96, the OS shuts down a few services (I know, not in your case where you already did that yourself).
My case from yesterday : I changed something again, with the objective of better sound. Well, apart from that I was crying over stupid Billy Cobham tracks (so yea, it worked), all kind of strangenesses happened throughout the hours of playing. One of the most important : the reading / processing of a next track stalled playback during that time (0.5 - 1 sec). What I think with this : the playback is now so much persistent (and looking at the software I can "see" that), that it destroys proper time slicing and once the "reading" thread becomes alive, it won't give away until finished.
And the only thing I did was changing the code a little, and really nothing explicit (but on purpose, which is something else).
Is all of the above the answer to your crackling ? Yes. Apparently you never noticed it, but you changed the means of playback and now things don't workout anymore. Btw, I think 50% of people experienced the crackling, which they in 95% of cases attacked by the wrong means (like changing Q1, Priorities). I say it's only a matter of let the OS settle with the services, some means to enforce that, and looking at it in a way actually nobody can. So it's not easy.
For me though, it is 100% sure that once you did not have crackles, but it starts, you just have to wait until things settle. This *always* goes along with Stop/Start, because once it happens, it won't go away by itself (and the waiting is a matter of seconds).
What would happen is there would be the opposite of a loud pop (like a split-second of silence) that sounded like a record skipped and it would happen right at the time the next track was loading into memory (probably about a second or two before the end of the previous track).
So this is what I was just telling about myself. I never had that before though, and you don't have that software version. There are just more ways leading to Rome (well, away from it, this case).