You may want to post in the G-Skill forums or support. There may be Bios timings and specific settings to use. Check out these posts
Also take a look at the AMD article on DDR3 frequency may offer a little insite DDR3 memory frequency guide
The OP's issue is not RAM speed related, it's that his mobo isn't accessing all 32GB of RAM.
The links you listed do address some of the common RAM speed issues that AMD owners experience, however. The FX CPUs tend to support faster RAM up to ~2133 MHz. with the right RAM and proper BIOS settings though as testing with real apps has shown there is little system performance gains with RAM above ~1600 MHz. as DDR3 RAM running at ~1600 MHz. on a CPU powered desktop PC isn't a system bottleneck. APU powered desktops can see minor system gains with RAM up to ~2133 MHz. as the GPU section of the APU can use the added bandwidth.