Is it possible to upgrade my mid-2011 MacBook Air i7 8GB to support 802.11ac?
You are correct 4GB it was a typo.Something is wrong there… I used to have a mid 2011 MBA and the maximum RAM that was available in that year was 4gb. Perhaps you actually have a 2012 MBA?
MacBook Air (11-inch, Mid 2011) - Technical Specifications
Processor and Memory
Powered by a dual-core Intel Core i5 or i7 processor and DDR3 memory.
2GB or 4GB of 1333MHz DDR3 onboard memory