Hi I have the same mobo and have 8gb ram installed and have had no problems so far 
NZXT Lexa S 
Gigabyte 890GPA-UD3H (rev 2.0) motherboard 
AMD Phenom II X4 965 Black Edition, Deneb Core, S AM3, 3.4GHz 
8gb Crucial Ballistic DDR3 1333mhz/PC3-10600 (7-7-7-24) 1.65v 
XFX HD 6970 ATI - AMD Radeon Graphics Card - 2GB
Western Digital WD6402AAEX 640GB Hard Drive SATA111 7200rpm 64MB Cache-OEM Caviar Black. 
WD 250GB 3.5" SATA 6Gb/s Caviar Blue Hard Drive - 7200RPM 16MB 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.