I recently upgraded my desktop from a single stick of RAM ( G.SKILL Ripjaws X Series 8GB 240-Pin DDR3 SDRAM DDR3 1600 to be specific) to two of them (same stick) but my PC only recognizes 12gb. I don't believe it is a problem with the slot because it recognizes 4 more gbs just not the whole thing. I changed slots anyway just to be sure though and no change. My mobo is the ASUS M5A99X EVO R2.0 and should support 32gb of RAM. I messed with the RAM BIOS settings to see if that would effect anything. After manual adjustment of all settings and rebooting there was still no change. I'm wondering if anybody else has run into this issue and found a fix for it. Thank you for any help.