Posting a new answer since it is 2019.
TLDR: AMD is now supported on both Windows and Linux via WHPX and yes, Genymotion is faster as it is using x86 architecture virtualization.
From the Android docs (January 2019):
Though we recommend using HAXM on Windows, it is possible to use
Windows Hypervisor Platform (WHPX) with the emulator. You should use
WHPX with the emulator if you are using an AMD CPU or if you need to
use Hyper-V at the same time.
To use WHPX acceleration on Windows, you must enable the Windows
Hypervisor Platform option in the Turn Windows features on or off
dialog box. For changes to this option to take effect, restart your
computer.
Additionally, the following changes must be made in the BIOS settings:
Intel CPU: VT-x must be enabled. AMD CPU: Virtualization or SVM must
be enabled.
Diff from 2016:
Virtualization extension requirements
Before attempting to use acceleration, you should first determine if
your CPU supports one of the following virtualization extensions
technologies:
- Intel Virtualization Technology (VT, VT-x, vmx) extensions
- AMD Virtualization (AMD-V, SVM) extensions
(only supported for Linux)
Most modern computers do. If you use an older computer and you're not
sure, consult the specifications from the manufacturer of your CPU to
determine if it supports virtualization extensions. If your CPU
doesn't support one of these virtualization technologies, then you
can't use VM acceleration.
Virtualization extensions are typically enabled through your computer BIOS and are frequently turned off by default. Check the documentation
for your motherboard to find out how to enable virtualization
extensions.