So I scored a R905 for $335 on flea-bay. 128GB RAM, 4 4-core 2.7GHZ opterons. Nice deal. Unfortunately, I can't seem to get it to accept an SAS HBA or RAID in any of the 7 PCI-E slots (2 X8 5 X4). One is a LSI 9207 and the other a arc-1883. No matter which slots I try either in, they get to the point where they are initializing and/or testing the PCI bus and just sit there. The slots work, since I tried several enet and/or infiniband cards and they work just fine. There is a dedicated storage slot, which did hold a perc 6i, but I can't use that slot, since it does not have a removable tab (nor do I have any guarantee it would work anyway). I suppose I could shell out another couple of hundred $$$ on flea bay for an officially approved Dell HBA which lists the R905 as a supported unit, but I'm reluctant without some hint it will work. It almost seems like the BIOS is not doing something required? I did try a couple of random LSI SATA cards, and they work fine, but that is no help. Any thoughts/tips appreciated!