HP is a commercial line for serious businesses they pack a punch in cost. You get good stuff though so be proud of your purchase.
I have been using HP/Compaq since about 1997 and the Proliant line DL,ML series has been rock solid from 1u,2u,4u models; They are more expensive now but you don't need many anymore to get the job done.
The fans spin extremely fast not like a desktop PC this is very high RPM please watch your fingers if you need to be working in it while it is on, I recommend not but turning it off first; The HDD and memory are very, very expensive