May I assume you have a Gigabyte motherboard? That's the only brand I have run across that uses the term GSATA.
The Gigabyte GSATA ports use a JMicron controller on the motherboard. Their performance is slightly lower than the other SATA ports using an Intel controller. There is a possibility some users might experience a driver issue when using the GSATA port with a modern ssd.
I recommend that you do not use the GSATA ports. Instead use one of the Intel ports. Don't forget to check for driver updates too.