Re: I'm planning on upgrading my RAM...
The recommended configuration is probably to run it in Dual-Channel. If your borad has physicaly 3-4... whatever the number is of slots. It is safe to use as many as you wish.
Keep in mind that if you put an uneven amout of memory sticks you will be running them in Single Channel. This is about how everybody is using their ram. Dual channel in simple, gives the ram a bit more of a perfomance boost. Unless you are an active gamer. You don't have to worry about Dual- Channel Ram.
AMD Athlon XP 2600+ Barton (running @ 2.21)--Asus A7N8X --1gb (2x512) DDR PC3200 --200gb WD 8mb cache 7200 RPM--40gb WD 2mb cache 5200 RPM --XFX GeForce 6600GT AGP 8x @ 588\1.14 --Creative Audigy2 7.1 ZS--CoolMax 400 wat PSU-- --Volcano 12+ CPU Fan--Overclocking Kit--Logitech Z-5300e's