CPU, GPU and motherboard
Hard drive, GPU and RAM
CPU, RAM and motherboard
It's actually a full rebuild
Correct Answer: CPU, RAM and motherboard

A brief explanation why…

There are many ways to squeeze additional performance out of an aging PC. Swapping your hard drive for a solid state drive or upgrading your graphics card might provide a speed boost depending on what you're doing, but changing out your CPU, RAM and motherboard is classically recognized as a platform upgrade and is typically performed when a full rebuild isn't really necessary, yet your Q6600 isn't quite cutting it anymore.

If your machine happens to be due for such an upgrade and you got that answer wrong, our PC buying guide and community forum can help you through the process of choosing and installing your new components.