when i put the second drive in, it was running HOT ! well, both of them were.
so i used thermal grease and then added a small HSF assembly.
not the drives run cool ! their purpose in life was to back up an old Xeon system. the shuttle SB51G with the P4 3.06 was about as fast as the Xeon 2.4, and it was 1/4 the size, so i thought - what the hell, another reason to spend money on computer stuff !
of course the project kind of experienced "mission creep". i realized that i would need to ventilate the case, too.
now the drives run warm, about the same temp as when there was just one drive in there.