Things that commonly affect framerates/Frametime.....
Temperature of CPU/GPU
Adequacy of Power Supply
Excessive background processes
Insufficient memory (RAM)
Insufficient graphics memory (VRAM)
Incorrect graphics settings
Corrupt drivers
Corrupt/damaged Windows system files
Failing/faulty hardware
If the graphics card was installed in a pre-built system, I'd consider replacing the power supply with a better unit....
If the difference between your performance and the performance from other benchmarks on the internet is 10 FPS then it cannot be the problem of your graphics card at all. In my opinion it has to do somthing with your system (consider disabling backround apps that take away some performance and you might gte 10 FPS more). Out of my exprience I also discovored that storages (HDD/SSD) that have low storage space result in some lags and little framedrops so try to kep your storage disk as low as possible or buying a larger storge disk because this helped me eliminating some of those lags and they were noticible.
I've tested this claim several times over the last few years and have been unable to reproduce this occurrence in any game.