I have been using a Gigabyte GA-7N400S motherboard. Recently, one of the capacitors on it went bad and so I decided to buy a replacement/additional/spare board, second-hand, although I am going to re-cap the Gigabyte one. The new board I bought is an Esys/Foxconn (board says 'Esys'; Googling the model ID came up with 'Foxconn') P4M 800P7MB(-RS2H?).

The Gigabyte board has an AMD Athlon XP 1800+ processor on it, along with 1 GB RAM. I have a spare AMD Athlon XP 2200+ processor I could fit into it instead (if it still works--currently in a board where all the caps went bad and the PSU blew), and the board will accept up to an additional 2 GB RAM. The Esys/Foxconn board has an Intel Celeron 3.3 GHz processor on it, along with 512 MB RAM. The board will accept only 1 GB RAM in total.

Which motherboard should I use as my main PC one, in terms of speed, as things stand? What is the minimum upgrades I need to do for a more powerful computing experience? What are my options?