Hi Andrew. I generally prefer to work at software rather than the hardware rather. If I am working at the hardware level, I just don’t tell my wife haa haa lol!! :)
Buuuuut. As far as tips. If you are willing to open that computer up. It may be worth checking to see if the CPU or any of the vents are getting dust build up in them.
The next general point to bear in mind. It does seem like 7200 RPM HDDs are noisier than their 5200 RPM counterparts. For some reason, it seem more noise equals more speed. If you are puzzled and want to know more detailed info than OS X provides. Maybe try looking into an option for downloading software like TechTool Pro. It can warn of general problems with battery, CPU etc. So in summary. Depending on your personal budget. Consider an SSD. The program from Micromat. Or maybe it is just a problem that needs to be endured. Sorry if it is the last one mate!