Well, this is most peculiar! Putting in another disk and setting that as your scratch disk should have sorted the problem. I think with 134 Gb of free space, the amount of RAM isn't an issue at all. My apologies if you've already tried this, but have you reset your preferences (trashed your preferences file) since you installed the new disk? If not, it's got to be worth a go. If you're not sure what to do, have a look here:
creativepro.com - Photoshop Tips: Trashing the Preferences File