On Tue, September 16, 2014 2:29 pm, m.roth at 5-cent.us wrote: > Hi, folks, > > I'm installing a RAID controller card for a large external RAID box in > a Dell server. I've got two riser slots available. Here's the question: > the controller card has some large chips on one side, and if I put it > in riser 1, those chips face downwards in the box, blocking ease of > cooling, while if I put it in riser 2, the chips will face up... but be > right over a large chip on the m/b that's got a heat sink. > I would use riser 1. If you use riser 2, you will create more resistance to airflow in area where already is one big heater. I assume, there are no separators of airflow going from front to end (or from middle where the set of fans are usually situated). My guess would be chips facing down have much less effect on effectiveness of cooling unless your configuration is such that airflow path along chips (i.e. underneath that board in riser 1) is totally blocked. Valeri ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++