Using:
wine 0.9.25-2.1
debian etch, kernel 2.6.18-4-686
dual core machine
1 Gb connection
7 dedicated servers on this box (fully optimized for just LFS hosting)
Yesterday night we had the mentioned problem of people who stopped seeing everyone else thus being a "ghost race" more than anything. I think that's the UDP packet issue.
We had this problem back when we were running a host in another machine with the same configuration but was used for other tasks and not just LFS. Anyway when we installed patch X on that machine, which uses the same kernel and WINE but has only different hardware and usage, the problem seemed to disappear. We used two servers on that machine with 60 people racing at the same time and everything went well.
Based on that experience we set up a dedicated machine with the same linux core and wine version, a faster connection and higher CPU power to have more servers this week. It resulted in the above mentioned problem happening very soon when we had about 130 people connected. And very soon I mean like 10 minutes, but I think it shows depending on the people connected and the time the server has been running is not an important fact. We knew this problem from long ago, when we couldn't have more than 12 o 13 people on the server because too many people caused the server to fail (in this way).
For reference, CPU was 3% at it's highest peak and bandwith usage was 18 Mb out of 1 Gb.