Nope, Nvidia's GPU.
of htop under ubuntu and wheezy (first two are ubuntu's). Note the picture where xserver is consuming 33% of CPU resources when Iceweasel was running (the CPU usage was hopping between 30 and 5 or so). Also compiz seems to be more resource hungry in Wheezy. Overall largest consumer is xserver. The xfce panel plugins don't seem that well-written either.
Edit: resizing some windows, mostly terminal, causes Xorg to peak; it often idles at ~40%.
Edit2: I just noiced, the kernel is 32-bit version, but my system has Core 2 Duo T7700. I've chosen the wrong installation media, but that shouldn't cause any problems, right?