[mythtv-users] ATA RAID Question

[Chris Thompson]

davatar (davatar at comcast.net) wrote:
> Also about "standard drives" keeping up with SATA drives, the PCI bus
> theoretical transfer rate is 133MB/s, with overhead it's much lower. Even on
> my nforce2 which is pretty good about it (pretty much nothing on the pci
> bus - all hypertransport) I can get about 110-112MB/s.  So ultra ata 133->
> SATA 150 makes absolutely no difference. My U3W 160 with a cheetah 15.2k
> only gets about 100MB/s :) No SATA drive is going to beat that.

The speed differences in SATA150 vs Parallel drives are, as you say, not
different, today. That last bit is what's important. You're right in saying
that the limiting factor is the PCI bus, but you assume that PCI is here to
stay, and in it's current form, it's not.

I'll admit that I pay little attention to the bleeding edge hardware arena,
but from what I've gathered, the future is PCI Express (Which is different
than PCI-X, see http://www.pcisig.com/). This new format should replace both
PCI and AGP by providing one set of slots with the same form factor and 
electrical spec, with slots being of varying speeds. So, your video card 
will be in a 16x PCIExpress slot, while various other 8x, 4x, etc. slots 
will handle other types of cards.

So, you've got a choice. Buy a drive today that works right at the limits
of PCI, and which will be just as fast if you upgrade your motherboard in a
year, or buy a drive that exceeds the current spec and will grow into the
new specs and be "unfettered" by current tech.

_______________
Chris Thompson