Topic summary
Crystalwell
Extracted from the Wikipedia article Intel Graphics Technology.
Haswell
The 128 MB of eDRAM in the Iris Pro GT3e is in the same package as the CPU, but on a separate die manufactured in a different process. Intel refers to this as a Level 4 cache, available to both CPU and GPU, naming it Crystalwell. The Linux drm/i915 driver is aware and capable of using this eDRAM since kernel version 3.12.