I have finally found a solution to this...after much forth and back.
First, You just can't play the game on a 64 bit OS.... sooner or later the game will crash and you get the 'out of memory' error...
After testing several versions of windows (Ihave a 2 year old PC with good specs. Nvidia 980 GTX card and 16 mb ram on an ASUS Maximus ranger VII motherboard) I have found that Windows 7 32 ultimate works fine. I have played several hours and even saved complex games and reloaded them wo errors (I could not do this in the 64 bit version).
When you run several programs while you play, the game may lag but you don't get the 'out of memory error'. I do not use any antivirus and installed it on a clean Win 7 32 install. It don't lag when u only play CC, it runs smooth and fine. I have tested for 2 mods wo error. The mods I use is Tiberium wars advanced and Tiberium essence.
Hope this can help as this is a fun game to play...
cheers, Jan