Some days ago I gathered information about MIDI and Latency (and even worse: Latency Jitter). I found this tool called "Miditest" which I think is very useful.
You just have to connect your MIDI OUT to you MIDI IN and run the Program. It will send MIDI Events to the output and reveice the returned events from the MIDI IN. At the end of the test it will tell you the mean latency and jitter times.
I have successfully used the tool on my Soundblaster Audigy. I think the tool is for Windows only.
Here is a link:
http://earthvegaconnection.com/evc/products/miditest/
Or just type "Miditest" into Google and it will be the first one in the result list.
If you did the test could you post your results here ? I am quite interested in it.
Regards,
Chri