Xbox has that right now. Some memory channels have 1GB chips while some have 2GB chips. So part of your memory space uses all channels and part uses more like

Xbox has that right now. Some memory channels have 1GB chips while some have 2GB chips. So part of your memory space uses all channels and part uses more like half. That GPU was much worse though. If that .5GB had been moderately slower it wouldn't have gotten the same attention. But because it was a weird backup path to that segment of memory, on a design that normally runs all segments in parallel, it ran at 1/7 the speed of everything else. Overflowing into it was devastating.