Well, to be honest, this is beta drivers from ATI, never released.
The reason is obvious, ATI4800 not supported in Win10 by ATI/AMD, only windows generic driver, which is... well, not as good as this beta. The point here is driver 100% stable, and running all other stuff perfectly more than a year now.
And answering the @JanH question, 98% load happens only when game run. Other programs/games never shows such high load.