I think that this questions answers for itself.
Buy the new GPU and then see how that works for you.
IF you see that the CPU is struggling and you want it to go faster, then obviously you need a new one, if it however does what you ask it to do, then there's no point in changing am I right?
Buy the new GPU and then see how that works for you.
IF you see that the CPU is struggling and you want it to go faster, then obviously you need a new one, if it however does what you ask it to do, then there's no point in changing am I right?