If you put it in a 1U case I would be very surprised if it didn't matter - I'm doing that with a very low power platform and the clearance between the memory an

If you put it in a 1U case I would be very surprised if it didn't matter - I'm doing that with a very low power platform and the clearance between the memory and the case only leaves a 2-3 mm gap, which I doubt would permit sufficient airflow for a normal passive CPU heatsink with a normal CPU power.