How much faster is a amd 64 x2 5600+ then a sempron 3400+ for mid range tasks?

ok i have been looking on tom's hardware for comparison of these two processors and the 64 x2 doesn't really seem the knock out the sempron in most taks like vid encoding, burning movies and etc ( but not gaming). So what advantages will i have if i go to a amd 64 x2 instead of my sempron it doesn't really show a huge difference of performance to me.