The additional memory is
July 2, 2012 at 9:01 pm
#7363
Aaron Ledger
The additional memory is likely of little, if any, benefit to HTPC applications with display resolutions of 1080p or less.
Fanless should be perfectly fine. Presumably the manufacturer has performed due diligence in making sure their cooling solution is adequate.
Of the three that you have linked, I would definitely advise against the 64-bit version because it cripples the memory bus bandwidth for only a $5 savings. Either of the other two options would generally be fine for HTPC use (even for most LAV Video + MadVR rendering cases).