From your performance graph I would agree that the system is I/O bound. I don't know how the Blocks system works with respect to updating data but one thing that is always important in a system with a lot of I/O (e.g. high usage databases) is to separate disk reads from disk writes. I have experienced large degradations in system performance after disks have been rearranged. The tricky bit is to identify these writes, since they could come from "innocent" activities like log files etc. As an extreme example it is sometimes recommended for systems running NTFS with frequent updates to files to have the Change Journal on a separate disk. Reads of non-fragmented files from disk that are not interlaced by writes to the same disk are very fast, so if you can identify processes that writes to disk and separate those writes to a separate disk performance would improve a lot. The problem could be if Blocks continously updates the files that are read since these writes are hard to separate and they would also lead to fragmentation. If this is the case a SSD could help since physical movement of the read/write head inside the disk is not an issue when switching between read and write. Since disks are pretty cheap I would suggest to install one in your current computer and make some tests. If you're going to build a new computer I would use the extra money on additional disk(s).
Since you guys were discussing the Q6600, I thought I'd pass this along. Looks like a decent buy @ $949. HP including 24" monitor. http://www.samsclub.com/shopping/navigate.do?dest=5&item=401746&pCatg=5816
Wouldn't buy that if any intention of running 3 or more monitors... it has the ubiquitous "el cheapo" mobo...
Yes. They put onboard video chip on $40 mobos. For a decent computer and especially if you ever want to run 3 or more monitors, suggest P35, X38, or newer. (Older 965P or 975X are very good, too.) HP has a a workstation line with x38's.. Dell also, the T3400.
Speaking of motherboards, any suggestions for mobos to mate to the Q9550? I need: - At least 8GB RAM, but would like to be able to go to 16GB later if needed. - Will have 6 SATA HDDs and 1 SATA optical drive (2 striped SSD's, 2 striped SATA's, and 2 independent high capacity SATA drives for backups). Onboard RAID sufficient for this -- or wiser to get dedicated RAID controller? - Two video cards to support four monitors total (2 * pci-e x16?) Any recommendations for a mobo?