On Sun, Jun 01, 2008 at 07:26:09AM -0400, Justin Piszcz wrote:
> On Sun, 1 Jun 2008, Justin Piszcz wrote:
> >On Sun, 1 Jun 2008, Justin Piszcz wrote:
> >>I have 12 enterprise-class seagate 1TiB disks on a 965 desktop board and
> >>it appears I have hit the limit, if I were able to get the maximum speed
> >>of all drives, ~70MiB/avg * 12 = 840MiB/s but it seems to stop aound 774
> >>MiB/s (currently running badblocks on all drives)..
> >Small correction, they are 7200.11 Seagate Desktop Drives (ST31000340AS),
> >not enterprise drives:
> Basically it appears I am hammering the southbridge as for this board the
> PCI-e (x1) slots also traverse through the southbridge.
> 6_SATA -> G965 ICH8
> 3_PCI-e -> G965 ICH8
> >From which has to ship that data across the DMI (2GB) link to the
> If one utilized a 12, 16 or 24 port raid card (but used SW RAID) on the
> x16 slot on the northbridge itself, would this barrier exist as the:
> GMCH<->CPU is (8.5GB/s)..?
> Also on the X38 and X48 the speed increases slightly:
> http://www.intel.com/products/chipsets/X38/X38_Block_Diagram.jpg (10.6GB/s)
> http://www.intel.com/products/chipsets/x48/x48_block_diagram.jpg (12.8GB/s)
> If one asks why would one need such speed?
It looks like graphic games are pushing the technologies to their
limits, which is good for us. I have bought X38 motherboards for
10 Gbps experimentations, and this chipset is perfectly capable of
feeding two Myri10GE NICs (20 Gbps total). This is 2.5 GB/s, not
counting overhead. So I/O bandwidth is a premium requirement today.
Other chipsets I have tested (945 and 965) were very poor (about 4.7
and 6.5 Gbps respectively if my memory serves me right).