The difference is too small to have any real effect on performance. If you consider that there are better and worse overclockable GPUs, silicon lottery and ofcourse manufacturer's OC, it's expected to have a difference.
If you really want to see if it's underperforming you need to play a game, preferably not an online one and then compare your performance with a SIMILAR system with yours.
Ok thanks alot for the info, looking more into this i made an OC scan with Msi Afterburner and got a boost of 110mhz on clock speed, and 200 on memory speed,
and now im getting a much better score , i'll need to see if the games run as smooth as before