1080 is still a crap shoot. Could be micron or samsung with GDDR5. If you have a 1080 OC edition it has GDDR5X which is all Micron. I bought a pair of 1080s when they first launched, one was samsung, the other was micron. The Samsung card would overclock on the Vram nicely while the micron was pretty much a dud.
Prudent thing to do is run GPUZ and be certain of what you have first. If its not GDDR5X memory its not going to do 11Gbps. If you decide to flash your VBIOS make damn sure you save the original first so you have a back out. What is loaded on internet sites has proven to be not reliable. You have to keep in mind that anyone can upload, including butt plugs that find spamming out a corrupted VBIOS is funny.
Without changing a thing in the VBIOS to get the Vram up you can simply OC it with a utility. The only time Ive seen Flashing a VBIOS as something that is actually beneficial is when you have a good cooling solution and you up the core and power limits.
“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein