Hi mate, all Gigabyte motherboards come with a 3 year warranty starting from date of manufacture so fine for the warranty. I've RMA's my board twice in the last 12 months & on both occasions got the board back within 3 days of me posting it.
Besides arranging RMA, you might want to include a detailed explanation of the issues you are having to ensure RMA understand what the fault is.
Other than paying for shipping to GBT (I paid £5.60 1st class recorded) you've not really got anything to lose. My board was gradually dying & it wasn't until it totally crapped out that I finally got my backside in gear & sorted out an RMA.