chewy_fruit_loop's questions

I have 2 servers on the same switch. I'm losing 5% of packets on ~16k pings between the two.

Below is my nasty ASCII diagram of the configuration of the network, all machines have a single interface.

 a       b
 |       |
 -- S1 --
      |
     S2
      |
     S3
      |
      c

a = Sun Netra 240
b = Dell 2950
c = my machine
S1 - S3 = 3 x Cisco Catalyst 2960G

pings from a -> b lose 5% data
pings from b -> a lose 5% data
pings from c -> a lose 0 data
pings from c -> b lose 0 data

I can't think of a reason that I'd lose packets going between ports on the same switch, when I didn't lose data coming from a different switch but still using the same port.

Can anyone throw any ideas my way please?
Thanks

I'm looking at picking up a fully loaded drobo pro this year (last quater). Has anyone actually found any benchmarks on it yet? I've seen many people saying the speed of the current drobo mk2 is less than steller. I'd be probably looking to use it via the iSCSI interface though which I've anecdotally seen at +50% over fw800 speed.

Has anyone actual evidence of the speeds yet?