solidworks speed

hi guys 

i need some help to understand why solidworks is so slow on my computer

my computer has 128gb ram, i7 core, 2 x nVidia Quadro M4000 and its still very slow when I do combine/intersect in tow pieces

the document has 250 MB and when I run combine/intersect is take too long ...

for example, I do combine/intersect yesterday at 2 PM and its still saying " solidowrks is busy running command

I dont know what do to … i dont know if i am doing something wrong … i dont know if the pc has a weak CPU …. i dont know anything 

please help me find a solution

Thanks

SolidworksGeneral