CPUs went from 65nm to 45nm to 32nm.
GPUs went from 65nm to 55nm to 40nm.
28nm as the next shrink for GPUs sounds right - but it will be a while before they get there, considering how painful the 40nm migration has been.
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The QuadFather: 4x4x4x4
4 cores (QX9650) / 4 GPUs (2x 9800 GX2) / 4x 2GB DDR2-800 / 4 hard disks (quad 320GB Seagates, RAID-5)