This link shows that the Mac Mini isn't wireless N capable. Kash is right. Sorry for the misinformation.
However, it also says this concerning network speeds.
Based on a comparison with Apple's 802.11g products. Comparison assumes AirPort Extreme network with 802.11n-enabled computer. Speed and range will be less if an 802.11a/b/g product joins the network. Accessing the wireless network requires an AirPort- or AirPort Extreme-enabled computer or other Wi-Fi Certified 802.11a/b/g-enabled computer. Actual performance will vary based on range, connection rate, site conditions, size of network, and other factors. Range will vary with site conditions.
It says speeds will be less if wireless G
joins the network, which is what I posted. It doesn't say anything about speeds slowing only if accessing files from G devices.
Sorry if I'm wrong, but several posts have been made on these forums which state the same thing I did. I did a search and none of those posts have been corrected as far as I can tell.
I'm fine with being wrong. Everybody makes mistakes, right?
I would like to know the correct information though!