I switched to another one. But the improvement is limited. for 3.6G it takes about 33 minites.
But the type is DW822A now, and supposed to be better than DW800A. I may just keep it considering the price $69.99 for a DVD+/-R writer. The disk is Fujifilm DVD+R(up to x4).
By the way, I bought at futureshop and it's on sale now, and will end today.