Most people who want a small form factor PC at home are those who will build it themselves, but not everyone has the time or inclination to do so.  That is where systems like the Lenovo ThinkCentre M91p come in handy.   Powered by a 2.7GHz Core 5-2500S, a single 4GB DIMM of DDR3-1333 and a 500GB HDD it is not overwhelming in its abilities but certainly qualifies as a low heat and low noise machine.  Silent PC Review thought that this machine would be better for an office PC than an HTPC as the Intel HD3000 struggles with playback in some cases but are very glad to see the rare 2500S in a system as it is hard to purchase as a seperate item but is quite nice with a turbo speed of 3.7GHz.

"The USFF version of Lenovo’s ThinkCentre M91p packs a significant punch in a small package. Utilizing an Intel "S" low power processor and a 150W external AC power adapter, it’s also incredibly energy efficient."

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