[Neuro Toxin]

The E3-1241 v3 looks good.

Asking for 40 slots @ 128 tick is a bit rich

[SM9]

Try running your server with -threads 24 +threads 24 (I am not sure which one so do both) It will spawn 24 worker processes for your gameserver which may improve your performance. And before anyone says anything, It actually works, The startup parameter is very deceiving because the source engine creates a separate process for each thread which is assigned, even sourcemod has 2 of its own worker processes.

[Neuro Toxin]

This wont magically fix and allow a 6 year old cpu that is under 3ghz to run 40 slots.