"Der Speichertakt der HD 7690M XT Grafikkarte ist 800 Mhz wie die HD 6770M !!! "
Ist vollkommen normal :
" The similarly named Radeon HD 7690M XT is based on the same architectural core as the 7690M, but offers higher clock speeds with GDDR5 memory. In essence, the XT variant is a renamed Radeon HD 6770M. "
Memory Speed * 900 MHz
* The specified clock rates are only guidelines for the manufacturer and can be altered by them.