That's going to depend on the games you want to play and the resolution you want to play at as some games are highly CPU dependent while others GPU. You will notice a substantial performance increase that much is certain, especially at 1920x1080.
Although you said you are on a tight budget, might I still recommend considering a whole system update? For $268 more you can get an "entry level" Ryzen system...
That is nearly 50% faster per core. And if you're an Amazon Prime member with the Amazon Store Card, that whole cart is eligible for 12 months no interest, $52.33 per month.