Hi i am thinking of increasing my ram to 4x2gb I allready have 2x2gb should i stick to the same make and type if i can get it or would there be a problem if i mixed makes, also my mobo has hybred graphics can i use it with the graphics card i have.    
NZXT Lexa S  
Gigabyte 890GPA-UD3H (rev 2.0) motherboard 
AMD Phenom II X4 965 Black Edition, Deneb Core, S AM3, 3.4GHz  
4gb Crucial Ballistic DDR3 1333mhz/PC3-10600 (7-7-7-24) 1.65v  
XFX HD 4870 X 2, PCI-E 2.0, 3600MHz GDDR5, GPU 
Western Digital WD6402AAEX 640GB Hard Drive SATA111 7200rpm 64MB Cache-OEM Caviar Black.   
Seagate Baracuda 500gb SATA11, 32mb Cache  
Corsair 750 PSU 
Zalman 9500    
Liteon DVD Writer 
24” Samsung SM2433BW Black Widescreen LCD, 1920x1200 
5.1 Creative Surround Speakers 
Logitech G11 Gaming Keyboard  
Logitech MX516 Gaming Mouse 
Windows 7 Home Premium 64bit 
Epson DX8400 All in one.