in my dell laptop (Inspiron 15R 5537[ i7-4500U with 4400 intel gpu + Radeon HD8850 ]) i have a issue with radeon drivers (both , crimson and catalyst). I tried various versions of drivers and still there is a problem with underclock GPU. I tried a lot of repairs but did not help. Gpu clock is maximum 300 Mhz after all. I think the problem is in the intel driver PCI bus.
Please give me some thoughts.