i'm just bought this laptop.why my HDD only 581GB not 640GB

i just do a partition to my hard disk.after do it the partition my laptop start running slow and my windows experience index down from 5.9 to 5.7.HELP ME !!!

it still the same.the experience index still not going up to 5.9 like before.when i starting windows it so slow than before and when playing game it a bit lagging.my brightness computer also suddenly become low after i do the partition.

i do partition at hard disk C since it only it and i using 3rd party software.i do big space at new partition(E) 400gb.my C now is 181gb .after do the partition i running the windows experience index and it drop from 5.9 to 5.7.so i feel like something wrong happen when i do the partition and the laptop kinda slow from before.i also forget what windows experience index that drop but i think it 'dekstop performance for Windows Aero'.I JUST BOUGHT THE LAPTOP 5 DAYS AGO

i donno which wrong.
i put that 400GB (E drive) as logical not primary.is it ok?

should i change my partition E (400GB) from logical to primary?

any good thing change it to primary?

can someone teach me how to update my BIOS.i want update the ver. 1.11