Question Dual booting with 2 different versions of win 10

[Dadrian Daedalus]

i have win 10 1909 installed on my primary partition (C drive),i am planning to install an older release of win 10(V 1803 to be precise) on another partition of a secondary HDD of my pc in order to run some older softwares & games-could that potentially have any adverse effects on my primary win 10 installation?

Also i usually keep fast boot enabled to make the boot time quicker-will installing 2 different versions of windows 10 on 2 partitions prevent fast boot on either OS from working properly?

 

[USAFRet]

What, specifically, runs in v1803 and does not run in v1909 (or later)?
While it is possible to have 2x Win 10 dualbooting on the same system, this often leads to issues. Especially if they reside on the same physical drive.

 

[Dadrian Daedalus]

They will be installed on 2 separate hdds

 

[USAFRet]

They will be installed on 2 separate hdds

For this, it is absolutely critical that you have only the one desired drive connected when you do these installs.

I still wouldn't recommend it, though.
Again, what specific applications are you expecting to give you problems with v1909?

 

[Dadrian Daedalus]

i have an older copy of win 10 1803 which doesn't include the meltdown and spectre patches

On my updated win 10 installation,some games run noticeably slower-it could be due to the fact that my system is pretty old or due to the recent updates that were included by M$ in newer builds.

hence i was thinking of trying v 1803 for a while to check whether any performance improvements are observed or not.

but after reading about the potential drawbacks of using this method,i have decided not to go ahead with it.I dont want anything to mess up my primary win 10 installation containing a lot of important data.