Maybe its the ambient noise levels but I wasn't able to tell how much noise the PCs were making in the stores. Too bad the reviews don't include a db figure.
that's always the problem w/ assessing noise in stores. as for the reviews, the ones that do system hardly even mention noise unless it's deafening.
hp and dell both measure their system noise, using iso7779 standards, and bury them somewhere deep in their sites.
dell -- http://www.dell.com/regulatory_compliance_datasheets
Check the "Sound Pressure Operator Position" for the spec closest to SPCR measurements; we do small systems at the same ~0.6m distance, but 1m for bigger systems designed for floor placement. The spl difference is less than 3 dba; more like 2 most of the time.
not sure where hp keeps them anymore, i think they're available somewhere; you might have to contact them.