You can typically see the L1/L2 SRAM cache regions just by looking for continuous patterns, then try to divide it into the number of cores or core groups you're looking for.
For CT scans, which use X-rays, the visible structure is very likely due to the metallic (copper) interconnect, clock- and power-delivery layers, which are generally quite different from the underlying transistors.
These layers are larger-scale, and copper also absorbs X-rays much more strongly than silicon.