Hi I got a quad core q9400 with hd 5570 and 4gb ram can I run gtav on low settings

Sgbrains2243 Why debate it? Simply buy it and try it out. If performance is unacceptable then do a steam return. You have to be under 2 hours of total play time. If you use key site, such as cdkeys, you'll get it cheaper but won't have the steam refund policy to fall back on.

Addendum: What you could do is purchase full price through Steam, try it out. If you don't like the performance then return it. But if you do like the performance, you could play up to 2 hours, initiate return. Then once refund has been approved, go and buy it on discount site. Just know that you can't use the steam code from the discount site until Steam approves the refund to remove the game from your account. Could be as quick as 4 hours, or 3 days. No way to know for sure how long the approval will take.