Radeon HD 8670m should be working but it's not

I have Inspiron 17 3737, Service tag  <ADMIN NOTE: Service tag removed per privacy policy> with Windows 8.1.

At first the AMD Catalyst Control Center didn't work well and the driver made problems, after installing and unstalling a lot of

Drivers i've managed to make it work. when i use the switchable graphics it's says it's working but it's really not!

i've tried anything and the latest drivers i've tried are:

http://www.dell.com/support/drivers/sg/en/sgbsd1/DriverDetails/Product/inspiron-15r-5537?driverId=C50TD&osCode=WB64A&fileId=3291482091&languageCode=EN&catego&dgc=SM&cid=266884&lid=5009361

and this

http://www.dell.com/support/drivers/sg/en/sgbsd1/DriverDetails/Product/inspiron-15r-5537?driverId=Y3FHH&osCode=WB64A&fileId=3287881735&languageCode=EN&catego&dgc=SM&cid=266884&lid=5009646

when i play simple game it's running very slow, i checked with HWiNFO64 which graphic card is running and the

radeon is never running.

any help? i'm desperate...