JEDEC made the GDDR5X memory standard official almost a year and a half ago where it launched at 10 Gbps and quickly hit 12 Gbps. Set to bridge the gap between GDDR5 and the upcoming GDDR6, the “G5X” standard is quickly catching up to and matching the speeds that GDDR6 will run at.
Specifically, Micron’s Graphics Design Team in Munich was able to achieve an impressive 16 Gbps in their high speed test environment. The team was able to hit 16 Gbps on a “meaningful sampling” of its mass production GDDR5X silicon which makes the feat much more impressive as it means these higher speeds are moving closer to reality than theory. Micron measured a PRBS11 (psuedorandom binary sequence) pattern read at 16 Gbps using an oscilloscope and also showed off a chart that compared the stable data rate timing margin versus data rate from 10 Gbps to 16 Gbps.
In addition to teasing the 16 Gbps memory speed (it will be awhile yet before we see products like graphics cards running memory at those speeds), Micron announced that it expects to being mass productions of GDDR6 chips in early 2018. GDDR6 will see a new (larger) FBGA1180 package, faster base sort speeds (GDDR6 will start at 12Gbps vs G5X's 10Gbps), and moving to a dual channel approach with channels that will have half as many I/O links (GDDR5X is x16/x32 while GDDR6 will be x8/16 per channel). It will be interesting to see how this move will stack up to G5X, but in theory Micron will be able to push clocks even higher (maybe even higher than 16 Gbps) by having more but simpler channels (and it may be easier for graphics card manufacturers to wire up their cards to the memory chips.
SK Hynix, who showed off its first GDDR6 chip at GTC, appears to be following the same I/O design as Micron with two channel memory at x8 or x16 per channel.
Are you ready for faster GDDR5X? Hopefully these new faster G5X chips come out soon to give AMD and NVIDIA a more appealing alternative to HBM and HBM2 for mid-range and high end consumer graphics cards since High Bandwidth Memory seems to still be suffering from limited supply and is holding the GPU guys back on being able to crank up the production lines!