Custom Modpack Framerate Issue

[JorgeF]

I have created a modpack for my friends to play on my server but one guy has a terrible frame rate of about 15fps when he try’s to play my modpack on the Server or Single Player, but he’s the only one having this issue.

He’s tried-

Reinstalling Windows

Updating his drivers

Upgrading to 16GB of RAM

Allocating more RAM to Technic

Update Java

Install Optifine

Lowered all Graphics 

Deleted and reinstalled Technic and the Modpack

He currently is running a - 

GIGABYTE RADEON 460 WINDFORCE 2GB

16GB RAM 

I don’t know the CPU

Any help or ideas would be appreciated because I’ve exhausted all my ideas.