Firewire pci card in B&W Expansion slot #1?

Question

I am using my Blue & White G3 as a server, including a role as backup server to an external firewire hard drive which is connected to a firewire PCI card in expansion slot 3.
The first expansion slot on the B&W runs at 66mhz, the other three at 33mhz. Since I run the server headless (access through Remote Desktop), I do not need to have the video card in slot one but could put it in another, slower, slot.
My questions are:
1.) Can I put the firewire PCI card in slot one and
2.) Will I get higher throughput?
Thanks,
Rich
G5 Dual 2.0   Mac OS X (10.4.3)  

Answer 1

FireWire 400 is theoretically capable of 400 MegaBits/sec. At 8 bits per byte, thats a theoretical maximum throughput of 50 MegaBytes a second.
A 10,000 RPM drive can source a single burst of data off the platters at about 50 MegaBytes a second. Write bursts can be slightly faster, because the data goes in the cache, but you have to write it to the platters eventually.
The 33 MHz slots are talking multiple bytes at once, so there effective speed should be quite a bit higher. I have seen a rumor here that bugs in the firmware limit the 33 MHz slots to a mere 53 MegaBytes/ second.
My assessment is: everything is topping out around 50 MegaBytes a second. Unless you are using a 15,000 RPM drive in the FireWire enclosure, you do not need to do anything extraordinary. Connect it in the usual way and it should do fine. The extra theoretical speed from the 66 MHz slot is unlikely to be seen in daily use.