the flow rate through the tap is probably due to the tap, ikea are s**t. imagine running a hose pipe and the waters not running that fast nip the end hey presto its an illusion less flow more pressure but you'll think its great cause its firing out.
Yes it could well be due to the tap. Though it isn't a tap from Ikea, as far as I know. It could be, it's one that we were given, and have had stored for a while and just used now.