Originally Posted by Monolyth
Naw, older PCI bus caps @ 133MB/s. Even at full Gigabit speeds you can't fill it. Of course all PCI slots share the same channel which is why PCIe is better.
One thing I found was a huge bottleneck for me on large xfers was simply the storage I was going to. Remember that as you get further into the center of the platter (more used space on the drive, the slower the drive will be. Right around 60-75% is where the drop off normally occurs. This isn't so bad with higher RPM drives as the faster speeds offset the time it takes the head to reach the inner platter. Be sure to run tests on your file-storage to ensure it can handle the load otherwise your system will throttle the connection and you'll get less then expected performance.
Yea that is what I was getting at. If he has anything else using the PCI bus it's going to be saturated in a hurry. 133MBps is just the theoretical limit. After you add overhead I've found it to be exactly 110MBps when I had my RAID controller on it. Nothing like a flatline graph at 110MBps for 95% of the drive test.