How to install Optifine Ultra 1.5.2 on the FTB Beta pack.
Download optifine 1.5.2 at optifine.net/downloads.php.
Then take that and click edit mod pack.
Go to the jar mods tab, and insert the mod.
I have an AMD Radeon HD 6450 and it works fine.Thijisrico, try useing a different shader pack...