Higher pps and bps don't directly mean applications will run faster, it has more to do with how high a load the switch/router can support.
Wire speed (i.e. 100% capacity) requires a certain amount of bandwidth. Generally when quoted for 64 byte sized packets, multiple gig ports 2x bandwidth for necessary bandwidth, and gig ports by 1.488 Mpps.
For example, 48 gig ports would require a fabric of 96 Gbps and about 72 Mpps. If a switch specs don't support wire speed for all ports, applications should only run slower when the device has reached its max perfomance and if a higher load is attempted. For example, a switch rated at 48 Gbps and 36 Mpps might deliver wire speed until more than 24 Gbps was attempted.
For a remote desktop application such as VNC, you shouldn't see much of any performance difference between switches (as also noted by Edison mention of VNC across 10 Mbps) unless the switch is overtaxed and/or a link or links also used by the VNC traffic flow are congested.
Depending on your needs, if something like the 2924 is insufficient, Cisco offers many other switches. I.e. you might not need to jump to the 4500 series to provide for your needs (probably also at a much lower cost).
