I have two hosted servers and I can get rid of one of them
The 840 has more 200GB disk and a slightly faster CPU, but the 1900 has 2cpux2core where the 840 is 1cpux4core. Both have same memory. So if all else is equal I'll keep the 840
But do you see any compelling hardware architectural feature of a 1900 ? Would its processing power be substantially different?
The 1900 shows SCSI in device manager, the 840 shows ATA SCSI.
Processing power and throughput will be important, so if you see any compelling reason to choose a 1900 over an 840 please comment.