Do you have a 64 bit system, and if so can you add more RAM?  Video editing in Photoshop on a 32 bit system with a maximum of about 2 GB of RAM available for Photoshop seems, well, not a good match.

I know very little about photo editing, but I do know Photoshop can barely breathe in a 4 GB system even on just still photos.

-Noel

Memory's relatively inexpensive nowadays.  8 GB may seem like a lot, but more is better.

Also, if your system can use it, consider ECC RAM because it will correct or catch errors that could otherwise result in data corruption.

-Noel

Jeff

I had to build a new system to run Premiere Pro CS5 with 1080p H.264 files from a Canon DSLR, and they are similar in that they are highly compressed, which means a lot of work for the processor. You are running Windows, so bring up the Task Manager and monitor CPU and memory usage while CS6 tries to play your video. I am betting one or both will be maxed out. There is a difference between playing the file in Media Player and Photoshop, because the former does not need to decompress the file on the fly. Photoshop does.

In order to satisfactorily view my DSLR footage on the timeline, I built a system with an 17 3930K six core running at 4Ghz with 32Gb RAM and a GTX570.  When I first tried this system it still wasn’t coping because the drives were not fast enough, and I had to create a couple of raid0 arrays.  I am now able to smoothly scrub through anything I care to throw at Premiere Pro. I have not tried video with Photoshop CS6, but I would imagine the same constraints would apply.  What we need in this thread is for people with mid spec’d systems who have tried CS6 with 1080p H.264 or AVCHD, to say how their systems faired. 

If Photoshop CS6 does have the same sort of system requirements as Premiere Pro, then you’ll find all the info you need over on the Premiere Pro hardware forum, But Bill Gehrke spends time here, and will likely have something to say.