I'd look at upping the amount of RAM in the box. 1GB isn't that much with the number of users you're sporting, also look at your hard disk array.. i.e. is it beefy enough to handle that many random I/O reads/writes. With that many concurrent users, I would think of nothing less than a 4 or 5 drive Ultra160 Raid5 array. And as for hardware cache on the controller, the more the better... but 64-128MB should be good. Also the normal things like keeping your OS and data on separate arrays, etc...