Using Open with an image sequence (checked) to make a timeline out of stills in Photoshop CS6.

I can do 866 images that are 2592x1944 (5M) and ~2100 KB each, no problem: photos process, it become a timeline I can play in PS, export video etc.

When I switch cameras and take images that are 3000x2250 and ~2700 KB each, I cannot even import 90 images.

The weird thing is Photoshop gives me dialog after asking for FPS which reads "This sequence has gaps". Then it appears to have a timeline, but on playing the timeline things hang and it skips from frame 1 or the first few, and turns to a transparent image. On the timeline the video block jumps to look like it starts at 12s (preceded by 12s of transparency) and nothing else happens except the playback marker continues over the timeline. Hitting rewind to first frame makes it visually look like a proper timeline, but nothing is available after the first few frames.

I can import 30 frames without the "This sequence has gaps", but not 45. Without the error, the video exports fine, with the error the video exports (30fps / med quality) but only has a frame or two, then black (blank) just like the timeline.

Photoshop 13.0.1 x64 Extended (still in trial period)
Win7 64bit on i5 2500k 16GB ram NVIDIA GeForce GTX 560 Ti
First camera is a Hero3 white, second camera is a Hero3 black

So what is wrong, or what should I look for/test?

attached is the timeline and blank canvas after trying to play.

Can't Import Sequence to Video CS6-photoshop_timeline.png