It may be a RAM problem. I would suggest checking the bios and make sure the memory is actually running at 1333 speeds. Sometimes the motherboard will automatically set the speed to a specific value (i.e. 1066), which could be what you are experiencing.
If not the RAM, I would then look at the hard disk drive. If you are using a 5400 rpm hard drive that could explain the problem, in which case you will need to get a faster HDD to fix the issue.
If it is not either of those, I would go back to the RAM and think that it is because you are only using 2GB and could upgrade to 4GB and you will feel a great boost in speed. Before purchasing new or more RAM you may want to take your system to a computer repair shop and let them check it out just to make sure it isn't something else, but I've built enough systems to tell you that going from 2GB to 4GB will definatley fix the problem, but should be your last resport after checking everything else out so you can save yourself some money.