Hi Matt.
Ok, got the capture and successfully 'unzipped' it.
(Sorry, I guess I'm using old software to do this!)

I see 12840 packets. The capture is a TCP conversation 
between two hosts using the SMB aka CIFS protocol.

10.194.217.10 is the client - Presumably Windows?
10.194.217.3 is the server - Presumably OpenSolaris - CIFS server?

Using WireShark,
Menu: 'Statistics > Endpoints' show:

The Client has transmitted 4849 packets, and
the Server has transmitted 7991 packets.

Menu: 'Analyze > Expert info Composite':
The 'Errors' tab shows:
4849 packets with a 'Bad TCP checksum' error - These are all transmitted by the 
Client.

(Apply a filter of 'ip.src_host == "10.194.217.10"' to confirm this.)

The 'Notes' tab shows:
..numerous 'Duplicate Ack's'
For example, for 60 different ACK packets, the exact same packet was 
re-transmitted 7 times!
Packet #3718 was duplicated 17 times.
Packet #8215 was duplicated 16 times.
packet #6421 was duplicated 15 times, etc.
These bursts of duplicate ACK packets are all coming from the client side.

This certainly looks strange to me - I've not seen anything like this before.
It's not going to help the speed to unnecessarily duplicate packets like
that, and these burst are often closely followed by a short delay, ~0.2 seconds.
And as far as I can see, it looks to point towards the client as the source
of the problem.
If you are seeing the same problem with other client PC, then I guess we need 
to 
suspect the 'switch' that connects them.

Ok, that's my thoughts & conclusion for now.
Maybe you could get some more snoop captures with other clients, and
with a different switch, and do a similar analysis.
Regards
Nigel Smith
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