Much lower benchmark scores, but same game performance after mobo/CPU swap

[XCalinX]

Hey folks,
I recently upgraded from an i7 6700k and an Asus Z170-A board to the Ryzen 7 1800X and the Gigabyte AX370 Gaming 5 motherboard.
I'm super happy with the CPU performance that is much higher in multi threaded tasks and benchmarks and the gaming performance is roughly the same, but I have a problem regarding some GPU intensive benchmarks, specifically Unigine Valley and 3DMark Firestrike.
I run 2 GTX 1080 Founders Edition cards.
In Valley, I get roughly the same performance as I was getting with one card before I added the second, while in 3DMark the GPU score also went down to what I was getting with one card. During these benchmarks, both GPUs are at around 45-50% utilization in MSI Afterburner.
The weird thing is that the 4K gaming performance is literally the same and both GPUs are at 80+ utilization all the time, in Battlefield 1 and SWBF.
I removed my driver with DDU and installed the latest one from the GeForce website but it didn't seem to help.
The only thing left is to do a fresh install of Windows 10, but I really don't wanna do that, I've been running this installation since I had a FX 8350, a year and a half ago, so this installation has gone through 3 different CPUs and motherboards and I have a lot of data on it I don't wanna lose.
Any ideas?
Thanks.
Edit: I can't remove my GPUs and reseat them because they're both watercooled with rigid tubing...

 

[RobCrezz]

Running the same installation through 3 different sets of hardware is never a good idea...

 

[tamsinmccormick]

What you have to realise is that guys like the Test ops in Custom PC Magazine test new kit with just Windows and their favourite benchmark software and three games. If like me you replace a Motherboard ,CPU and Memory and retain all your collected programmes intact then the benchmarks you obtain will be reflected in that and not resemble a "naked" runner with only three games to cover its rear end !!
A lean machine will always run faster on a test bench than on a well used home computer . My computer has 8f5 shortcuts on the desktop so that collection will take a toll on performance especially all the attendant start up services . However when I upgraded to an i7 7700K , 16gb DDR4 at 3000mhz and an ASUS Strix Z2707F Mobo . from an I7 4790K system I did notice a few improvements that made the spend and the work worthwhile . I recommend leap-frogging a system or two or you will spend too much money and not see much reward. I waited about 3 years between systems and a different 3 years for VGA cards. That way it feels like constant improvement without overdoing the old plastic !!
Don't worry about BenchMarks look for your own satisfaction in your individual setup and you will feel much better. !!