Hello people!
This is my first post here as I just wanted to throw in my 2 cents here. I hope to become a regular poster here ! But I do want to explain how I view this 8 GB thing.
1) 8GB of VRAM is not an advantage in most situations EVEN at 4k. That is true. However, it can ammount to something in
Crossfire support. Or people that
mod their games heavily CAN see it being used up.
Modding is a huge thing for me, absolutely superior to graphical fidelity and even frame rate for me. One of the major reasons why I am a PC Gamer even (after backwards compatibility and cheaper long term costs, before emulation).
The other reason is that some people do not
upgrade every year or two or three... or four. The ability for your card to allow you to max two of the most important Visual Quality aspects ( Texture Quality and Model Quality) even in future titles, is great. EVEN if you have to turn down some other things, this means that for us, the R9 390 has this advantage.
My last GPU lasted me 6 years. The ATI 5770.
If I had listened to people saying back in the day that the 1 Gigabyte model is somewhat pointless... well it would have bit me in the backside. That 1 GB of VRAM allowed it to play even games like Witcher 3. This is the same thing here. I am certain that 2-3-4 years from now there will be games whose texture and model quality sliders would benefit from more than 4 GB of VRAM. And for those that upgrade like me, even more slowly, at 5 or 6 years... it will be a godsend. We DO exist.
Being a PC Gamer means I should be able to choose the best performance/quality settings. So no, it wont struggle at all in 2 years at 1440P... most options would still be on Ultra or High (though not all, I admit). I can manage though, as long as the heavy hitters can be done well on my card. And my 1 GB ATI 5770 allowed just that. So I guess... the 8GB R9 390 will manage too.
2) Power Consumption is not so simple. The first thing is Idle Draw or draw under not very punishing scenarios is good on the R9 390. Another thing is that FRTC (frame rate target control) does exist and can be used to great effect in many of the most popular titles of today and yesterday.
Meaning it will exist... but it wont be a major difference to the pocket.
Just my opinion as a person who upgrades much more rarely than most of you