We have a small datacenter with lots of 2960G's as access-switches and a 4510R as a aggregation switch.
Performance is relatively good, but after new HP servers with the HP Multifunction adapter seems slow when connected to 2960G's. The performance problem is not consistent as some servers have ~1G speed to the HP server, but others vary between 10 and 200Mbit. All other servers reach ~1G between each other, so there is no duplex problems involved. All servers connected to the same switch as the HP seems to have ok speed's but when the 4510R is involved in switching beetween the HP and other servers, it seems to be a speed problem between some servers. When connecting the HP to a port in the 4510R everything seems OK.
Anyone heard of a problem like this? "Everything" has been tested, cables, software (relatively new)..
Depending on the type of blades used in the 4510 and the way the uplinks are connected, there may be a considerable overbooking in the paths between servers.
I believe the backplane of the 4510 does something like 6Gig per slot. (may depend on the supervisor, I did not re-check)
This can easily be saturated via a 48-port gigabit module.