cant explain why games are lagging

Dear Dolphin Forum experts and members,

I just registrated here in this forum to find a solution for my problem:

My Notebook

Intel Core i7 2760QM (2,40 Ghz, 6MB, 4C)
6 gb 1333 mh ddr3 dual
128 gb SSD, +320 gb HD
2 GB DDR5 AMD Radeon HD 6990M

i just tested 2 iso files (Mario Party 8 and Super Smash Bros. Brawl) both are lagging (Video as well as Audio)!

graphic card is working properly. (actually the vent. isn't doing much more sound after starting dolphin)

What could be the solution for my problem ?

Thank you in advance!

Best

Cheesus

PS: in case you are having some question please do not hesitate to ask