Vellix :
I have h81m-k,8gb ram and 1tb hard drive
There's no way the i5 4460 bottlenecks a 750 ti
Indeed, the 750 ti is too weak for that CPU
It's time for a GPU upgrade as well. Sadly mid-range GPU prices go through the roof this days so this might not be the best moment to buy one.
anyway, depending on the game and how GPU bound the scenario is, the i5 4460 might be enough for a GTX 1060 or 1070 even
Now, I think some H81 boards can OC. Though they aren't really meant for OC since they lack VRM heatsinks and don't have as many power phases as Z87/Z97 boards I have seen people hitting +4 GHz on an unlocked CPU
So I would consider buying a used i5 4670K/4690K. They run at faster speeds out of the box and can OC a litttle bit.