Poor graphics performance on some boot ups

[dxzone12]

I am having a very odd issue with my computer that has happened since it was first built a couple years ago and I have tried to fix it a few times but given up every time, so I thought I would ask here.

 

First describing the issue: I cant find a pattern to it but sometimes when I boot up my computer it performs poorly in anything graphically demanding such as benchmarks and games. The problem persists until I restart the computer which usually fixes the problem although sometimes it requires multiple reboots. I use valley benchmark to test if I am on what I call a good or bad boot. In a good boot it benchmarks around 55 in the first scene and on a bad boot it can be anywhere from 10 to 40 but it is always consistent until restarted.

 

Secondly what I have tried: I am fairly sure the graphics card is not the issue as switching my 970 out for a 980 from another computer the same sort of problem occurs, although in that case a good boot is around 65 and a bad is around 40 consistent with the difference in performance of the two cards.

I have also tried doing a clean re install of windows several times and have made sure that it is in UEFI mode.

I have also tried tweaking various settings in the bios but i can not remember which ones at this stage.

 

Third SPECS: The specs are the same as on my profile.

CPU: i5-4590

Mobo: Asus Z97-A

Ram: 4x4gb Kingston Hyper X Fury DDR3 1866mhz

GPU: Gigabyte gtx 970 G1 Gaming 4gb

Storage: 1 850 evo 250gb and 1 WD blue 2TB

PSU: 750w coolermaster vanguard s

Operating system: Windows 10 Pro 64-bit

Bios Version: 2801 (the newest I could find and it also occurred on an older version)