An article about AMD creating memory to keep up with increasing GPU speed:
http://electronicdesign.com/displays/best-2015-high-bandwidth-memory-helps-gpu-deliver-performance?NL=ED-001&Issue=ED-001_20151120_ED-001_454&sfvc4enews=42&cl=article_1_b&utm_rid=CPG05000002085202&utm_campaign=4265&utm_medium=email&elq2=4d56277a376e4a5ab0d3e0a0139a07ba
