> The PCI bus is only capable of 133MB/s max. Unless you have dedicated
> SATA ports, each on its own PCI-e bus, you will not get speeds in excess
> of 133MB/s, 200MB/s+ I have read reports of someone using 4-5 SATA
> controllers (SiI 3112 cards on PCI-e x1 ports) and they got around 200MB/s
> or so on a RAID5, I assume that was read performance.
Um, I *do* have dedicated SATA ports, each pair on its own PCIe bus.
You might recall I wrote:
>> This is 6 ST3400832AS 400 GB SATA drives, each capable of 60 MB/s
>> sustained, on Sil3132 PCIe controllers with NCQ enabled. I measured
>> > 300 MB/sec sustained aggregate off a temporary RAID-0 device during
>> installation.
I also included examples of reading 60 MB/s off 6 drives in parallel
(360 MB/s aggregate), and reading off RAID-5 at 277 MB/s.
To be specific, the narrowest bottleneck between drive and RAM is the
250 MB/s PCIe link shared by each pair of drives. To quote approximate
one-way bandwidths:
1.5 Gb/s SATA 2.5 Gb/s PCIe
Drive <--------> Sil3132
Drive <--------> Dual SATA <--------\
\
Drive <--------> Sil3132 \ 16x HyperTransport 2x DDR
Drive <--------> Dual SATA <-------> nForce4 <-----> CPU <-----> RAM
/ 4000 MB/s 6400 MB/s
Drive <--------> Sil3132 /
Drive <--------> Dual SATA <--------/
150 MB/s each 250 MB/s each
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