Yes,warranty will be void.Always get such upgrades done at authorized service centres unless it is something very basic which does not involve opening more than 1-2 screws(e.g.in many laptops ram can be upgraded by simply opening a small panel at bottom & inserting the ram in empty slot.Of course you can't even do this for acer laptops as acer put stickers everywhere so even opening a screw is impossible without voiding warranty).