AMD’s RDNA 2 “Big Navi” flagship will reportedly feature 16GB of VRAM on a 512-bit memory bus

Rumour has it that AMD’s “Big Navi” RDNA 2 flagship will feature 16GB of GDDR6 memory, at least according to 3D Center, whose citing a report from Chiphell’s wjm47196. 

If these rumours are to be believed; with Big Navi, AMD’s avoiding HBM2 memory, opting instead for GDDR6 memory across a large 512-bit memory bus. For context, AMD hasn’t released a GPU with a memory bus this large since the release of the R9 390X in 2015, a graphics card which utilised sixteen memory modules at launch. 

With a 512-bit memory bus, AMD’s RDNA 2 flagship will feature a doubling of memory bandwidth over AMD’s RX 5700 XT if the company continues to utilise 14Gbps GDDR6 memory. If AMD opts for faster 16Gbps or 18Gbps modules, AMD’s RDNA 2 flagship will deliver 2.28x or 2.57x increases in memory bandwidth respectively. If this is true, AMD’s preparing something crazy for its RDNA 2 flagship. 

(AMD’s R9 290X Reference PCB (16 GDDR5 memory modules on a 512-bit memory bus))

With 16GB of GDDR6 DRAM, AMD must be using a 512-bit memory bus. It is the only bus size that works if AMD plans to offer even memory access and more bandwidth than today’s high-end GPU offerings. A 256-bit memory bus can support this much VRAM with larger capacity memory modules, though a bus size that small could result in DRAM bandwidth issues. 

With 16GB of DRAM and a 512-bit memory bus, AMD will be able to deliver more bandwidth than both next-generation consoles and offer as much GPU/Video memory as either console offers in combined CPU/GPU DRAM capacity. This design should allow AMD’s “Big Navi” graphics card to age well when compared to both new consoles, offering more bandwidth, VRAM, a common graphics architecture and more raw gaming performance when it launches later this year. 

The only downside of AMD’s approach is the need for so much graphics memory, as having this many GDDR6 chips will add to the material costs of AMD’s next-generation graphics cards. On top of that, the 512-bit memory bus will take up a lot of die space on AMD’s flagship RDNA 2 graphics silicon, which has its own manufacturing costs. Regardless, if AMD needs this much bandwidth to deliver leadership gaming performance, it will be worth it.