Postpone a CPU/motherboard upgrade as long as possible. Upgrade your motherboard and CPU only after you exhaust the other possibilities. A major CPU/motherboard upgrade involves a some serious computer surgery and has some possible negative consequences:
A CPU/motherboard combo is one of the most expensive upgrades you can make to your computer. First consider upgrading random access memory (RAM) and your video card. Adding RAM and a faster video card is (usually) cheaper than upgrading a CPU/motherboard combo. And, depending on the types of applications you run, the RAM/video card upgrade might provide a better performance boost than using a new CPU and motherboard.
A side benefit is that the longer you postpone a CPU/motherboard upgrade, the more of a performance jump you get when you finally take the plunge.
A CPU/motherboard combo is one of the most difficult upgrades to install. To facilitate this upgrade, you have to take out every adapter card and unhook every wire and possibly even disassemble parts of your case — and then do it all again in reverse.
A CPU/motherboard combo has dependencies. No matter how fast your new motherboard-and-CPU combo might be, it still depends on your existing adapter cards — including video, sound, modem, and port cards — to take care of putting (respectively) video on your monitor, sound in your speakers, and Internet data in your browser.
You might have to scrap your existing memory modules and power supply. Using a new CPU/motherboard combo might force you to dump all the memory modules you’ve collected over the past few years and that low-rated power supply.