if you only have 2GB of RAM, what system specs are you running?
That’s low for any HD format.
Set your Dynamic RAM to 0 and be sure any antivirus is disabled completely.
Douglas Spotted Eagle
VASST
Certified Sony Vegas Trainer
Aerial Camera/Instructor
Set your preview to “Preview/Auto.”
Set Dynamic RAM to “0”
Turn off/disable any anti-virus and any background apps.
This should cure your problem, assuming you have a reasonably fast system.
Douglas Spotted Eagle
VASST
Certified Sony Vegas Trainer
Aerial Camera/Instructor
Depending on the encode, mp4 files can be very CPU intensive.
You will get the best quality from your MJPEG files but as you noticed, they are large.
Try .mxf
Douglas Spotted Eagle
VASST
Certified Sony Vegas Trainer
Aerial Camera/Instructor
HDV or AVCHD are the two HD formats you might look at for editing in Vegas (and other apps) that fall into your price range.
Sony’s NXCAM or Canon’s A1 cams are super, I’m a big fan of XDCAM EX, but it’s out of your price range unless you can find used.
Douglas Spotted Eagle
VASST
Certified Sony Vegas Trainer
Aerial Camera/Instructor