When it comes to upgrading your computer hardware, regardless of your operating system preference, there's always questions of does it work, how fast does it work, and does it actually make the system faster (or is there a bottleneck elsewhere).
Linux hardware shopping up to this point has largely been using Google to search for hardware, reading a lot, download and compiling packages if there is no integrated support, cross your fingers / wish for luck, and hope your hardware purchase is backed by a good return policy if there are Linux problems.
The Linux Hardware Compatibility lists on the Internet from different distribution vendors and other community sources are of limited benefit. Their certification does not usually mean much and it is not too detailed what "tested" or "certified" actually means. Are they using a graphics card with the useless VESA driver? With an open-source driver? With a closed-source driver? Etc. For more information on this particular topic, see my recent post entitled Canonical Puts Out A Hardware List, But It Falls Short.