Downloads on 2.4GHz band is faster than 5GHz band

I recently bought a Asus RT-AC66U router and i have a computer connected on the 2.4GHz band and one connected on the 5GHz band.
If i have downloads going on the computer connected to the 5GHz band,and then if someone starts some downloads on the computer connected to the 2.4GHz band,this computer gets all of the download speed.
Is there any way fix it so the computer connected to the 5GHz band has priority over the one connected to the 2.4GHz band for the download speed?