What do you mean with "low compression"?
Do you mean big files (=not very compressed) or very small files (=lots of compression, but less data)?
That question might seem stupid, but as i said, the 230mb episode i tried first lagged just as much as the 650mb episode i tried later. I didn't notice any difference...
By the way, is it normal that it takes ages for stuff to be transferred to the sd card? x__X
The (hopefully) 8-bit 1080p film i downloaded for testing purposes is large (10gb), but i still don't feel like it should take more than 3 hours for it to be transferred... i've been sitting here and waiting, because i've tried it a few times already and it always broke off at some point (last time when it was nearly finished!). Grrrr! Maybe it would be faster if i took the sd card out and put it directly into the computer...
I think it's kind of a bother taking it out, but then again, much better than sitting next to the computer for 6 hours trying to transfer a video file.

edit: I just realised that maybe you mean 480p encodes?

Because the resolution seems to matter much more than the filesize (makes sense when i remember the added load on the cpu is per pixel). I've already downloaded one to test it... just haven't gotten around to it yet.