My Book 3.0 Slow usb 3.0 speed NEED HELP!

Hi i am new to the forums so first wanna say hi everyone!!!

Ok so i just purchased the my book 3.0 that came with the usb 3.0 card. Plugged the usb 3.0 card in and i can see the hdd no problem but i noticed my tx speeds are really low. so i compared to the usb 2.0 slots on my computer and im getting ~60-70 mb/s on 3.0 and upwards of ~80 mb/s on 2.0. I have made sure my firmware and drivers are up to date even reinstalled a few times still nothing. My setup is a couple yrs old so i was wondering if it might be the actual motherboard. So i went and looked up any infomation on my mobo and what i need to make this card work for me. My setup is a kn9 sli mobo with amd athlon 64 am2 5400+ processor. This board has 2 Pcie x1 slots. So what i am wondering if the Pcie x1 is too slow for the actual card? Upon doing my research i was finding the pcie x1 slots had tx rates of up to 2.5 gb/s so reading that i would assume i would get better tx speeds than what i am. Any help with this would be greatly appreciated.

Your motherboard needs to support usb 3.0.  If you don’t have a dedicated usb 3.0 port to connect to it wont work.