This shows several combinations of heatsinks (active, with a fan, and
passive). We tested this by monitoring the temp. of the CPU (via the
BMC), while the system was idle (for several minutes), then starting multiple
instances (1 per core) of heat, running those for ~20 minutes, stopping heat,
and waiting 'til the temp returned back to the starting temp.
We have two machines, that have two configurations of heatsinks (with and
without a fan) and fans (that force air towards the CPU). The graph below
shows that the 6 x circular fans (high RPM, with high yaw, attached in 3 rows
of two fans) keeps the CPU cooler than the 2 x squirrel cage fans: it also
shows that the passive heatsink keeps the CPU cooler than the heatsink with
a fan attached (the fins on the active heatsink are substantially smaller).
This is a link to the xmgr image source file.
This is a link to the postscript file
used to generate the following .png