I was wondering whether it might be worthwhile upgrading my computer to get an overall speed increase. I haven't really changed anything (apart from the RAM) since I built the machine in early 2010 (nearly 5 years ago).

Currently I have the following:

Motherboard: Gigabyte P31-ES3G
CPU: Pentium E6300 @ 2.8GHz (socket LGA 775)
Graphics: ATI Radeon HD4550
Memory: 4GB DDR2 (I don't use anywhere near 4GB, and I can't remember the exact specification).

Does anyone have any suggestions for upgrades? I know its a bit outdated now, but I don't mind getting second hand or NOS parts.