While it was reported a year ago that AMD's Tonga XT GPU had a 384-bit memory bus in articles sourcing the same PC Watch report, when the Radeon R9 380X was released last month we saw a Tonga XT GPU with a 256-bit memory interface.
The full Tonga core features a 384-bit GDDR5 memory bus (Credit: PC Watch)
Reports of the upcoming card had consistently referenced the wider 384-bit bus, and tonight we are able to officially confirm that Tonga (not just Tonga XT) has been 384-bit capable all along, though this was never enabled by AMD. The reason? The company never found the right price/performance combination.
AMD confirms 384-bit bus available on Tonga, just not enabled on any product, including 380X. Didn't find a perfect perf/$ slot.— Ryan Shrout (@ryanshrout) December 4, 2015
AMD's Raja Koduri confirmed Tonga's 384-bit bus tonight, and our own Ryan Shrout broke the news on Twitter.
So does this mean an upcoming Tonga GPU could offer this wider memory bus? Tonga itself was a follow-up to Tahiti (R9 280/280X), which did have a 384-bit bus, but all along the choice had been made to keep the updated core at 256-bit.
Now more than a year after the launch of Tonga a new part featuring a fully enabled memory bus doesn't seem realistic, but it's still interesting to know that significantly more memory bandwidth is locked away from owners of these cards.