Wow, I should have just asked the model number
Anyway, the 4600 appears to only take 333MHz (PC-2700) memory. I found some pretty good deals for you. It just depends on how much RAM you want.
Though let me break something down for you first... The term "bank" basically means to group. If you bank two sticks of 512MB, then it becomes 2x512MB and it can be referred to as a bank. Now, you could put just one stick of 1GB in one slot and it would equal the same amount. Though like I'll mention in just a bit, banking allows for faster access of memory. This is why it's wise to go with 2x512MB instead of 1x1024 (1GB) whenever possible.
I'd definitely recommend going either 2x512MB banked once or 2x256MB banked twice. Both setups will give you 1GB of memory, but banking up the 4 slots your computer comes with will enable the NorthBridge to communicate with more RAM at once (faster overall performance). Though the 2x256MB banked twice will fill up all your slots, so I'd actually recommend the 2x512MB bank if you are planning to use it in combination with your current RAM or if you think you might upgrade the RAM later on.
If you want the very best performance, I would recommend going Dual Channel. If you just want a bit better performance, then Dual Channel is not needed at all. (Dual Channel basically allows a bank of 2 sticks to act as one while having the speed advantage of banking.)
I'll go ahead and list some good RAM choices, however, I will not list any Dual Channel - if you would like to get some, just ask and I'll happily find some (there's plenty of choices for your computer, so do not fear
). Everything below will be in order of greatest size and performance to least.
Of course, if you would like to bank two sticks together, you would really have to go Dual Channel to get the full affect, but you don't have to. If you do not go Dual Channel then you will simply have to put the RAM in the next available slot(s). Dual Channel requires the bank to either be in slots 0 and 2 (first and third one) or in 1 and 3 (second and fourth one). Note that this is for a motherboard with only 4 RAM slots.
Ok, hope that helps in some way.
If you want to buy one of those, yell at me to get on AIM and I'll help you through it - same thing for installing the RAM in another computer.