Upgrade your kernel. Either via smxi to liquorix or towo, or via experimental to Debian's 3.6.
Try installing a more recent kernel - towo, liquorix or debian experimental. smxi can help.
Hey guys,I just updated my kernel with SMXI. I use the liquorix sources and am running i686 with PAE. I have 8gb RAM. Until now, all 8gb were recognized. After the upgrade to 3.14-6, only 3.45gb were recognized.