Compare PCI RAID Controllers 2782 and 2757

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Moving to a model 810 iSeries server from model 720. I have two proposals from Business Partners. One says the 2782 RAID controller will be sufficient, and the other says we will need the 2757. Does anyone have any experience with either of these? Can anyone offer a comparison? Thanks.

[Guest.Visitor]

A #2782 PCI-X controller: 12 disk drives, 40MB write cache, two Ultra SCSI buses. A #2757 PCI-X: 18 disk drives, 235MB of write cache (compression takes it to 757MB), up to 4 Ultra SCSI buses at 160MB/sec (versus 80MB/sec on 2778 and 4778). PCI burst rate is 532MB/sec, four times higher than 2778 and 4778s. The new controller also supports SCSI bus tagged command queuing, which yields faster response times under heavy loads, and has new hardware-assisted array parity checking and cache memory scrubbing algorithms that are five times faster than with prior cards. The net effect is when you combine the use of these controllers, either of the the new 15K RPM disk drives, and PCI-X slots or expansion towers can see a factor of three performance improvement in their disk subsystems.