Re: Marvell 88SX7042 [4 Port SATA PCI-Express x4] Support/Questions

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From: Grant Grundler
Date: Monday, May 26, 2008 - 5:34 pm

On Sun, May 25, 2008 at 10:47 AM, Mark Lord <liml@rtr.ca> wrote:
...

The bottle neck here is with the four disks.
Modern 1TB 7200 rpm disks have raw throughput rates up to around
100MB/s. Anything in the last 4-5 years should do better than 60MB/s.

In theory, ~16 disks (4 disks per 7042 port using Port Mulitpliers),
one should be able to hit 200+ MB/s per 7042 port and approach 900MB/s
total. Getting more than 900Mb/s will depend on the chipset. IIRC, the
MMRBC of 128 bytes will result in about 15% protocol overhead in the
PCI-e link.
Bigger PCI-e "burst" will result in dramatically less overhead (IIRC,
256Byte == 9% overhead.)

hth,
grant
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Re: Marvell 88SX7042 [4 Port SATA PCI-Express x4] Support/ ..., Grant Grundler, (Mon May 26, 5:34 pm)