SQL Server 2005

AMD 4-way dual core, so 8 procs.

Maxed out.

1000-1200 concurrent connections

2200-2500 Transactions per second

Minimal pagine 2-5 pages / sec

4 gb of ram still available out of 32gb possible

Do Disk Queue, % disk time less than 10 %, spikes of course.

100 % cpu utilization, i'll see 400-500 runnable spids with a wait type of SOS_SCHEDULER_YIELD.

Tuning like crazy, everything we can find, even resorting to NoLocks in many places and dropping referential integrity.

New server on the way, Intel 4-way Quad core, hopefully it will help.