Originally Posted by WolfDV
good point; mine are both on the pci-x 133mhz bus at the moment; maybe moving one to the unused pci-x 100mhz bus would have some gains?
anyone else have any thoughts?
Because it's Saturday and I'm feeling lazy I'll quote this from my initial post: "Although I am using unRaid and only have to worry about the PCI-bus bottleneck when doing parity, I didn't want that to be a bottleneck. While I could still theoretically reach it on the PCI-X bus with this build, it's gives me a much higher ceiling and in real-world use PCI-X should be plenty of bandwidth. (Two 8 port cards = 16 drives. Both cards share the PCI-X bus which is 1064 MB/s. So: 1064 MB/s / 16 drives = 66.5 MB/s per drive). This should be plenty given unRaid's tested, real world throughput. Plus unRaid right now only uses 16 drives. So: 16 drives - 6 sata ports on mobo = 10 drives on the PCI-X bus. 1064 MB/s / 10 drives = 106 MB/s per drive."
So, even if your using newer versions of unRaid that support 20 drives and you have all 16 ports of the two PCI-X cards filled, you still should see 66.5 MB/s throughput if ALL the hard drives are being accessed. As we are using unRaid this only happens during parity checks.
So, personally I wouldn't worry about it. As long as the server is able to serve your media or files at acceptable speeds, then... For media reads you should be able to easily maximize the read throughput of the hard drive(s) the file(s) are stored on (depending on how many concurrent streams you have of course).
Theoretically, though, if the buses are separate, you should get faster available bandwidth available for your hard drives. Remember, I'm a guy who knowingly bought a processor for my unRaid server that I knew was way overkill. So if you feel the "Need for Speed" then who am I to tell you not to. If I was building new, I'd definitely look into this and probably separate the PCI-X cards on the different buses just on principle.
It would be interesting if someone tried it both ways and did some testing and posted back with the results.