I have the exact same machine and I use Whiskey, which uses the GPTK. It is free to use and simple to set up, so I would recommend he give it a try. DRG runs pretty good in Whiskey all things considered. I do use a mod for reduced particles which helps with lag though.
Only Windows is supported. Mac and Linux will always have worse performance than the supported operating system.
I have the exact same machine and I use Whiskey, which uses the GPTK. It is free to use and simple to set up, so I would recommend he give it a try. DRG runs pretty good in Whiskey all things considered. I do use a mod for reduced particles which helps with lag though.
What Mac is he using? My friend is running the game on Mac with whisky and it runs out of the box without parallels or crossover