pe1950 fan speed control?

[Tom Rockwell]

Hi,

We have 20 pe1950s in a rack each with 16GB and 2 xeon e5335 each.  They 
are nice and they run our jobs fast, but boy is the back of the rack 
hot.  The temp rise on these is pretty high (I don't have a measurement 
though).  Is is possible to make the fans run faster? I understand that 
they run fan speed low to save power, but that results in a high 
temperature rise through the rack.  What if i wanted to tune the airflow 
through the rack to match the room's air-handlers?

Thanks,
Tom