Yes the Gpu is.
Is it a pci-e based card.
Or are you using something like an A8 or A10 cpu/gpu.
I see your memory is rated at 669Mhz, DDR 3 so the speed rating is 1333Mhz.
The reading at 669Mhz is only One Channel you have to times it by two because its DDR Double Data Rate.
Data read and write at the same time 669 x 2.
If you are running a Gpu cpu combo then the Gpu is crippled by the DDR 3 memory.
GDDR 4 or 5 memory you find on a Pci-e based graphics card is much faster because it is local to the graphics card.
And can handle more bandwidth or data pass though per cycle or clock speed.
Slow memory chokes a card along with its Memory and the with of the Bus in speed.
DD3 64bits GDDR 128bits 256bits of data per clock cycle more data in one pass or clock cycle.
Processes larger amount of memory in one clock cycle where as 64 bit would have to do four clock cycles to equal it taking more time to process data.