Couple of questions on Video Card memory

[Phalanx]

1. How does the amount of memory have to do with performance?

2. What does the memory bandwidth mean? (what does 256bits of bandwidth mean?)

3. What does 2.0nano second memory mean?

thx

[spyder003]

1. Amount of memory isn't as important as you think. Type of memory (DDR - DDR2 - GDDR3) and memory speed is most important.

2. 256 bit is the width of the bus from what I understand. (Somebody correct me here) I know that 256 bit cards do better in AA/AF applications. 128 bit cards don't handle AA/AF so well.

3. Can't help you with that one.

[Phalanx]

thx for the help, i've done some research and this is what i have found out, the speed of the RAM in "ns" gives you the speed of the memory, what you do is lets say you have 2.0ns memory, you do 1000 / 2.0 = 500 = 500mhz (1000mhz DDR) and so if you wanted to find out how much bandwidth you will get, you'd do the bus width (lets take 128bits) and divide it by 8 to get it in bytes so we have
128 / 8 = 16
then you multiply that by 500 (our memory speed)
16 * 500 = 8000
now since memory is nearly always DDR, we multiply by 2
8000 * 2 = 16000

so the memory for this graphics card (a 6600gt if ya haven't already guessed ) is 16 GB/s of memory bandwidth

anyone correct me if im wrong please?