Difference between ASUS Z170-A and ASUS Z170-PRO Motherboards

Solution
In a nutshell the Pro:

- Supports faster RAM
- Drops the old VGA plug
- Has 1 more PCIe lane
- Has 2 more fan headers
- Has improved built-in sound

Basically better sound, slightly better overclocking capability, and a few more slots for additional hardware.
In a nutshell the Pro:

- Supports faster RAM
- Drops the old VGA plug
- Has 1 more PCIe lane
- Has 2 more fan headers
- Has improved built-in sound

Basically better sound, slightly better overclocking capability, and a few more slots for additional hardware.
 
Solution