bob, I know you like to pick on me, but here's where I'm coming from.


GPU Memory Interface Video RAM
GTX 460 192-bit / 256-bit 1GB / 1GB
GTX 470 320-bit 1.2GB or 2.5GB
GTX 480 384-bit 1.5GB
GTX 560 256-bit 1GB
GTX 560 Ti 256-bit / 320-bit 1GB / 1.2GB
GTX 570 320-bit 1.2GB
GTX 580 384-bit 1.5GB or 3GB
GTX 660 192-bit 2GB
GTX 660 Ti 192-bit 2GB
GTX 670 256-bit 2GB or 4GB
GTX 680 256-bit 2GB or 4GB
GTX 760 256-bit 2GB or 4GB
GTX 770 256-bit 2GB or 4GB
GTX 780 384-bit 3GB
GTX 780 Ti 384-bit 3GB
GTX Titan 384-bit 6GB
GTX Titan Black 384-bit 6GB
GTX 960 128-bit 2GB
GTX 970 256-bit 4GB
GTX 980 256-bit 4GB
GTX 980 Ti 384-bit 6GB
GTX Titan-X 384-bit 6GB
GTX 1060 192-bit 6GB
GTX 1070 256-bit 8GB
GTX 1080 256-bit 8GB


So, while I'm sure there is plenty of math involved, I think we can safely use a cheat sheet and say...

GDDR5/X 128-bit/256-bit = 1/2/4/8/16/32GB
GDDR5/X 192-bit/384-bit = 1.5/3/6/12/24GB

The only GPUs which deviate from this are the older 192-bit x60 GPUs, which only came with 1GB or 2GB each. I also leave out the 512-bit memory interface because AMD is the only one who has used it in recent times, but it follows the same guidelines where it's just twice of the 256-bit interface.

Quote Originally Posted by mbox_bob View Post
HBM1 is 1024 bits wide.
I was only going off of what AMD prints on their website, and what the sites which reviewed and benchmarked both the R9 Nano and R9 Fury X were stating, but I know very little about HBM beyond that.

Quote Originally Posted by AMD
Ground-breaking performance requires big bandwidth. AMD’s latest innovation delivers more than 3x the bandwidth per watt over GDDR5 along with a 4096-bit memory interface for incredible new advances in power and efficiency.