Ok so I just tried this little app https://www.userbenchmark.com/
The amount of info it figures out after it has run (about 5 mins) is great. Lots of info is spat out and you can then switch out one part of your rig like CPU and it will show you the % improvement. It can work that out due to the many submitted user benchmarks.
It can also point out if your hardware is running slow compared to others. e.g. if GPU is under performing then you may have put it in a x16 slot but that slot is only running at x4 bus speed.