To help decide if the Virtual Private Servers (VPS) available from UCB-IST would be acceptable as a Cspace deployment platform for UC collections, I set up identical instances of Cspace v1.0 on a Slicehost server and one on a VPS in the UC data center. The two configurations are not identical, the UC VPS has slightly less memory, but they are roughly comparable (1.8 GB vs 2.0 GB).
To ensure that the two Cspace instances (UCJEPS and BGCSPACE) were the same, I duplicated the instances by copying all of $JBOSS_HOME and all of the MySQL files from UCJEPS server to BGCSPACE. That instance has just under 370,000 collection object catalog records, 8,780 person records, 49,455 organization records, 3,903 loans, and 23,974 relations.
The result was that BGCSPACE, the UCB VPS, was slightly faster.
Server startup time: UCJEPS - 2min. 5sec
BGCSPACE - 1min 10sec.
Login time: UCJEPS - 20sec (This includes time to load records since the landing page is the "My Collectionspace" page.
BGCSPACE - 8sec
Search time: UCJEPS - sec (Search for JEPS10097)
BGCSPACE - 3sec
Create time: UCJEPS - 7sec (Minimal new record with only the one required field)
BGCSPACE - 6sec
Modify time: UCJEPS - 8sec (Modified a single text field)
BGCSPACE - 7sec
Auto-complete time: UCJEPS - 9sec (Entered firstname Robert, which returned a list of 126 names)
BGCSPACE - 5sec
While this is by no means an exhaustive performance test, I think it does indicate that the VPSs are at least as usable as the Slicehost servers.