JEDEC announced final specification for GDDR5X, the successor to GDDR5, it don’t have much bandwidth as HBM or HBM2, though it’s a lot easier to implement than the HBMs, with GDDR5X, fewer modifications needed to the GPU design to use it.
“GDDR5X represents a significant leap forward for high end GPU design,” said Mian Quddus, JEDEC Board of Directors Chairman. “Its performance improvements over the prior standard will help enable the next generation of graphics and other high-performance applications.”
GDDR5X allows for up to 14Gbps of total bandwidth and because it’s based so heavily on its predecessor, it’s pin compatible though highly internally revised in order to facilitate actual advancements in memory speed and bandwidth without making something entirely new. How JEDEC and Micron have done this is by increasing the prefetch by double, mandating the use of Phase Locked Loops and Delay Locked Loops as well as being able to transmit data at a rate that’s quadruple the actual clock speed. In other words, it’s fast. For comparison, GDDR5X running at the top-end 14Gpbs could potentially provide 448GBps of full bandwidth, which isn’t too far off of the memory bandwidth of the R9 Fury X.
Micron, one of the leading manufacturers working on GDDR5X, estimates around a 10% power consumption decrease at the same VRAM size. VRAM sizes of 4Gb up to 16Gb can be used with the new specification. The GDDR5X maybe the choice for lots of new cards, reason HBM2 might not be affordable, despite AMD’s efforts to implement HBM in all segments of their GPUs. Now all GPUs can enjoy a healthy bandwidth increase for very little, if any, cost increase.