Hi all I’ve got an Alienware m18x r2 with dual nvidia 675M cards. I have noticed that not many games support sli any including Fortnite. So I was wondering what’s the best option of upgrading them. I’ve read multiple posts with different or opposing things stating on one post everything runs fine but on another there’s many problems. These posts are pretty old though so not sure if these glitches have been fixed. There’s things about 10 series cards not working correctly due to power supply issues. I’ve looked into the newer 1660ti’s specs and it doesn’t seem to require much power but there’s nothing out there that shows compatibility with my laptop. Only thing I can find is up to 1060m and anything above is not recommended. As these posts are pretty old I’d like to get some updated advice before I do anything. 
Thanks for any advice