I'm using 'movie edit pro 14 download plus' with 1gig of ram, single core, 3.4ghz processor. I'm importing MP4 files from a Samsung DV camera. I downloaded the Magix MP4 codec which imports the files fine, have tried mixdown after editing, but the files 'often' playback slow and jump, stop, skip etc.??? Any suggestions appreciated.
Anyhow, it seems you have too little ram, in my opinion at least.
I've had the same problem when I edited high resolution movies with barely meeting the specs given by the program.
My solution was actually to switch to Magix MEP 14, since it needed less computer-power than that other edit-program I had bought.
I edited HDV though, not .mp4. Eventhough they both are demanding codecs (highly compressed), and a bit similar.
But I've seen another guy claiming problems with samsung .mp4-files on my search for "mp4", so there might be a compatibility-problem..
By the way, I have 2 gig ram and 2 gig dualcore cpu.