Typically, table-level snapshot versioning has a minimal impact on performance.
Buffer consumption may increase slightly if multiple users are using different versions of the same database page simultaneously.
Version management requires some overhead, but the effect on performance is minimal.
The thread control, which determines how many processing resources a user gets, and the sweeper controls, which use a small number of threads to sweep dirty data pages out to disk, have a minor impact on performance.
Disk space can sometimes become an issue. Storing overlapping versions has the potential to use a lot of disk space, depending on the number and size of versions in use simultaneously. Metadata and database page versions are retained until they are dropped, either at a RELEASE SAVEPOINT or when the last transaction that can see a given version commits or rolls back. The space is then reclaimed.
Delays due to locking are minimal. Individual commits, rollbacks, and checkpoints might block other read or write transactions, but only very briefly.
All of these performance and disk use factors only affect your system in the degree to which you take advantage of the SAP Sybase IQ concurrent read and write capabilities. Disk space requirements in particular can vary widely, depending on how long write transactions take before they commit, how many read transactions take place during write transactions, the number of rows these transactions affect, and whether you allow the release of data pages at interim savepoints.