Loss is a function of frequency and length of the cable run: the higher the frequency or the longer the cable run, the greater the loss. Since you say you get satisfactory performance on 800 Mhz, then I would say you don't have a real problem. However, RG8X is not known as a true low-loss cable so you could, in theory, do better.
If by load you mean resistance or ohm rating, it is a nominal 50 ohm cable.
I subscribe to the principle of if it isn't broke, don't fix it.