Hi, What is the difference between a WD 80 GB w/ 2MB Buffer, and a WD 80 GB w/ 8MB Buffer? Will files copy/move faster? Is there a performance increase? If so, by how much?

Are you capturing, decoding, rendering? Those functions certainly may benefit and they are all video intensive. The buffer is a temp storage area. The disk buffer is an area of the hard drive reserved for RAM, to speed up access to data on the disk. The buffer serves as the staging area for data so that the processor can also perform other functions. So, a larger buffer size, then more information can be temporarily stored and then the faster it can be accessed, both written to and read from.

Your hard disk has the slowest access times of anything in your computer. To mediate the problem, a buffer is provided so that when files are read (typical larger files, which when unfragmented are arranged linearly), the buffer can read as much as possible and pass it swiftly along to the CPU or RAM. But in reality, the buffer is much more practical. When your disk gets fragmented (i.e. files are spread out in pieces across the drive), as all disks tend towards, your hard drive has to make extra spins to linearly get all the pieces (basically - don't put this in your thesis). Why? Let's use an example (without a buffer). File A is spread across the drive in different places. As the disk is spinning, the reader is picking up the pieces of the file and sending them where? To the main memory (RAM) or the CPU (but that is another situation, forget it for now). But to get to the RAM requires the extra step of going through the OS (very slight performance penalty, but its there) and typically to the memory reserved by the program that called the access (a little more slowdown if the program is doing something). We put buffers on hard drives (little bit of RAM, just for the drive) to gain a little performance boost. The hard drive RAM now can hold the file as it is being accessed, without involving the CPU, the OS, or the program (directly). The data is placed in (transparent) memory directly. From there, the data is quicky sped to wherever it should be going. The buffer also serves to read metadata (or filesystem information) ahead. Oh, and there is a performance increase on all disk operations. Calculating how much would be measured in ms and would depend entirely on real and virtual entropy (randomness).

I think buffer is similar to cache interms of CPU cache. Of course the more is better. Maybe I'm wrong, but I think it applies to cache pretty well.