Sansa Clip+ | rockbox 3.13 | Problems playing back selective tracks

[Groovist]

Hello.
I've had two kinds of issues, one of which I've solved. I believe they are codec and\or processing power related, but that's only a slightly educated guess.

1. Most .ape files had problems playing back from both SD and internal memory. The problems with those files were audio glitches (stutters or skips) accuring in consistently in certain spots. It appeared not to be a problem with copying files onto the player, since I did that several times. The player behaved weirdly too - it was struggling to react to any button inputs.
My solution was converting the files to .flac .
I'd imagine it to be a codec problem or something like that, clusters of data that unable to be read fast enough, optimisation problem...
I had one or two files with that extension working fine (though the player was still a little panicked) though.

2. Recently I've been having problems with playing back regular .flac files (roughly the only kind of format I use), a specific batch of them to be exact. The problems result in crashes, freezes or track skips (after playing a portion of the track). Issues seem to appear at random times, playing back different files among the certain few.
Slight visual glitches occur too when entering menus during those track playing.
I don't really know what could cause those.

Some info:
The Sansa Clip+ is less than 2 years old. I had almost no problems with running rockbox on it other than the ones above. I don't use any sort of processing on tracks (EQ, Dithering, etc. are all off, I only rarely mess around with boosting bass). I don't use playlists or the database to access files. There is still a decent amount of space on the internal memory and SD card.

Thanks in advance.

[saratoga]

You'll need a much faster player if you want to play APE:

http://www.rockbox.org/wiki/CodecPerformanceComparison#AMS_AS3525v2_w_47_24MHz_PCLK_40ARM926EJ_45S_41

Check the flac files for errors, bad tags, etc. 

[Groovist]

That's what I suspected.
The flac files should be fine, since I play them on my computer with no problems.
I'll have to figure out how to check the tags and all, but I don't think that's it. We'll see.