3 Gigs of ram is pretty decent but the speed upgrade from 556 mhz to 800 mhz might help.

I'm unsure why you want the second hard drive? Are you saying that you record your gameplay as you play videogames? Getting a second hard drive won't speed up your system but you could put them in a RAID-0 array (stripping) where they act like one hard drive and that would basically double their effective speed. However, I would not recommend doing that because if either of the hard drives fails you lose all your information, and there's a good chance of that. I bet the thing which would make the biggest improvement for the least money would be to upgrade to a Solid State Drive instead of a traditional HDD. They are way faster and if you install windows on it you'll notice it boots up in a fraction of the time.

The 9800 GT is actually a bit old, you could upgrade that too if you're mostly playing video games.

You won't get an accurate answer in here without a computer make and model. For all we know, your PC is already maxed out with ram.

EDIT: I gotta laugh at the thumbs down idiots. NO ONE can give you an answer WITHOUT these details PLAIN and SIMPLE!!!

EDIT: The 64 bit means NO such thing. It means a 64 bit operating system can handle more ram dumbass It does NOT mean your motherboard can! Now you want to pit your computer intelligence with my 40 years experience in them or do you want to provide a model number and get a CORRECT answer? I've got 3 motherboards in my shop right now that are 64 bit mobos and can ONLY hold 3 gigs of ram Forest! You want help in here, PROVIDE details or find another site to post your question.

First: Walmart does not sell RAM, I hate to tell you.

Second: HDD do not affect performance besides loading times, and you would only see an increase you got another and put it in RAID 0, got a SSD, or got a HDD with a higher RPM than you currently have (probably 15,000RPM since I bet you have one with 7,200 RPM).

Third: The RAM would increase speed, especially if you got a dual channel kit like you said. Assuming you buy the proper RAM and it works.

Again, Walmart does not sell RAM. Only retail store besides a PC store that would sell RAM is Bestbuy, and they have a very limited selection.

EDIT ----------------------------------------------------------

JUST SO YOU SEE THIS: WALMART DOES NOT SELL RAM FOR COMPUTERS.

Yeah buy a ram , your computer is good!

ram is always nice to have extra of, you can never go wrong with getting more of it...unless you have like more than 12 already hahah