That's pretty bizarre. Why would a faster boot affect colours?Disabling fast start is a good thing for other reasons though. If you dual boot, every time you swap operating systems there's a chance of fast boot corrupting your drives. You'll possibly lose any recently changed files. I've had this happen multiple times, until I found out that fast start is a well known culprit.
How was performance in DCS and what kind of graphics settings did you run?
I had a good solid 4 hours in it last night and thoroughly enjoyed it. DCS Is a joy and downloaded Fallout 4 VR to try tonight. Looking forward to your 2nd review mate 🙂