This is, I am sure, a naive question.

I literally don't know what to search for in Google to get an answer to this...

I have an old dual processor Pentium II (that's 2!) with each proc running at 350MHz.

I have a RAID 1 card in it with 2 SATA drives, and a gigabit ethernet card. 192MB memory, and a VERY bare bones Windows 2000. It works fine as a plain file server and nothing else (it literally runs no programs, just the OS).

But I have a nagging suspicion that I am holding the system back because of the processors, or the bus pseed, or the memory... but I have no idea. I mean, the drives are on a separate controller, and it has GB Ethernet, so the fact that it's old hardware shouldn't make a difference. Right?

Someone help an old-schooler out

The total bandwidth of the PCI bus is limited to 133MB/s, so you're likely going to run into limitations simply by having the RAID controller and gigabit network card on the same PCI bus.

RAID operations shouldn't require too much CPU power, but if the gigabit card doesn't have TOE capabilities, I can see your CPU limitation being a problem.

Here's a quick test for you. Grab iperf and dump it in the system32 folder on two machines (one of which is the file server). Set up another computer to run an iperf daemon with a 1MB TCP window. Run iperf on the file server to connect to the daemon (also with 1MB TCP window) and set it to run for 30 seconds. Watch your CPU usage in task manager. I can tell you that even on my Q6600 based system, I see the CPU usage go up a fair bit when transferring large amounts of data over the onboard gigabit card.

The GigE controller will more than max out the PCI bus by itself. Full duplex GigE operation requires approximately 250MB/s throughput (1000Mbit/s / 8 = 125MB/s * 2 = 250MB/s). This, of course, discards the TCP/IP overhead, CPU overhead (if the NIC doesn't have TOE) and a few other factors, but the end result is that the PCI bus is taxed beyond its capabilities just by the GigE NIC.

While it's true that file serving doesn't require that much CPU power, it does require good file and network subsystems, which require good buses to work on.

Honestly, unless your system has 64-bit PCI slots and there are seperate PCI buses that would allow you to put the RAID controller on one bus and the GigE NIC on another bus, which may the be case since it is a dual PII workstation/server board, there's no need to do that much testing because the PCI bus is, without a doubt, your bottleneck.