That's 1440p, not 2560p. When you talk about resolution you use the vertical number.I just downloaded and played their 2560p version
552mb file for 2 minutes of video!
Resolution is 2560x1440, it's 33.5mb/s and it takes about 100-115% of CPU to run it, perfectly smoothly in quicktime X, though it's obviously using 1 core and some change.
Looks good.
Still, that's a large file size for not much time!