Photoshop :: CS5 Crashing With Intuos4

I just bought a new Intuos4 and it's been a total nightmare ever since.Previously, I had a Wacom Graphire2 and worked great, Photoshop never crashed.Now, I'm having some big time issues with CS5 crashing.

Specs:

Intel duo core 3 gig
3 gigs ram
More than 1TB hard drive space
ATI Radeon 4670 with hardware acceleration turned on

Randomly, when I try to save a file, CS% just hangs and does not complete the save. This happens with 'save' and 'save as' at random times. If I try to change the file format (TIFF) for example, same thing happens.

It seems to happen once I've been working on the image for 5 minutes or more. If I save every 1 minute it's successful. But when I start getting into the 500 history states or so, it crashes on save.For example, if I am working on a file named "Ocean", I will work on it for 5 minutes or so and then select "save" or "save as" (doesn't matter which one).

It then begins to save the file, but under the name "~psAE.tmp" and the file size is about half of what it should be. The file I was working on (Ocean) remains untouched. It just loses anything that I worked on since the last time it did manage to save successfully.

So in other words, selecting "save" doesn't overwrite the file, it creates a new one called ~psAE.tmp but the file is corrupted and useless. The original "ocean" file is fine and untouched. Selecting "save as" does the same.