Just out of pure curiosity, how many slots do you think a server like the following could handle?

Dual Xeon Harpertown E5405 - 4 x 2.0GHz (thats eight cores total)
12GB of DDR 667 ECC
windows 2003
pretty much everything tweaked as best as I know how.
Virtually unlimited bandwidth.

I know I ask this quite a bit, but I am always curious to see what other people think. Also if you would have any suggestions as to what would be better? We try to run our servers with the latest and greatest of everything.

I would say 320 100 tickrate slots running at 100%. Course you dont want 100% so then just bring the number down to 250ish maybe.

And HOLY CRAP 12 GB XD.

Yes, we run a lot of COD4 servers as well as Americas Army and they run a lot of memory. That and with certain memory leaks different games can end up using a ton of memory, so we try to give that a cushion. That and memory anymore is so cheap, especially when you get it in bulk

As long as the load is balanced evenly though, you can get a bit more than that. Actually not to sure exactly, but we never run our servers over a 40% load at peak times, or I should say we don't run any one core over 40% load.

Yeah lol. You gotta always monitor your servers to see their load.