Why is Powernap not available for other MB's such as the MBP mid 2010 model for example?

It's only available for Macs that have Apple-branded SSDs. I have a third-party SSD in my MacBook Pro (late 2011) and it doesn't work either.

Sorry,

Clinton

No, it won't be updated. It's only going to work with Apple SSDs, period. There's a notation on the Mountain Lion features page that says "Power Nap requires a Mac notebook with built-in flash storage. May require a firmware update." And that means Apple supplied built-in flash storage.

Clinton

I have a 2010 MBP 6,2 with an aftermarket SSD. My machine gets mail and notifications while asleep, but I do not have any powernap pref box in energy savings under 10.9.1

I do not have an Apple SSD. I have a Crucial M4-CT512M4SSD2

Apple did replace my MB last Fall under the video fault problem (for free after 3 years.....thanks Apple), but it stills identifies as a 6,2 Boot ROM MBP61.0057.B0F

I wish I could shut off this powernap feature, but have no access to it.