I also have invisible coins on some levels. For example in the second world in the first castle level all the blue coins are invisible using EFB copy to texture. They are visible using EFB copy to RAM, but the game runs with lower fps.
Case: Gigabyte GZ-X1
PSU: FSP Aurum Gold 700W
Motherboard: Asus P8Z68-V LE
CPU: Intel Core i5-2500K
RAM: Kingston 8 GB HyperX PnP DDR3 1600MHz CL9 KIT
VGA: ASUS GeForce GTX 560 DirectCu II TOP
OS: Windows 7 Professional x64
PSU: FSP Aurum Gold 700W
Motherboard: Asus P8Z68-V LE
CPU: Intel Core i5-2500K
RAM: Kingston 8 GB HyperX PnP DDR3 1600MHz CL9 KIT
VGA: ASUS GeForce GTX 560 DirectCu II TOP
OS: Windows 7 Professional x64