I recently purchased a new hard drive for my 3.5-year-old Macbook; it was getting very slow and even opening folders would cause the computer to freeze. So I decided to buy a 250GB 2.5" Hitachi Travelstar Z5K320 5400RPM SATA 7mm Notebook Drive with 8MB Cache from OWC. (I transferred the data to the new drive using Carbon Copy Cloner.) Although I didn't expect the hard drive to perform faster than the original (since the RPM is the same), I'm a bit disappointed by this new drive. The computer isn't freezing up as much as it used to, but I still have to force quit applications pretty frequently. Opening applications like iPhoto can be a hassle, and large PDFs scroll very slowly. Was I wrong to purchase a new drive? Was the issue something else entirely (e.g., RAM?). I have 1GB of RAM (512 MB in each bank), so should I get more? I'm currently running Snow Leopard, and I don't want to switch to Lion because I've got PowerPC apps and not enough RAM. Let me know if you need any more info. Thanks!