5GB will be good, I tried running some stuff with 5k resolution, Ran slow but AWESOME. Some UE4 tech demos, looks OUTSTANDING, but running with full 7-8gb Vram? The 970 sli will be on their good for nothing knees, beggin' for Xtra mercy. Our cards as of now like I have stated once before, ain't fast enough to fully utilize the 8gb Vram, even if it did, how fast would the card run actually? DIRT SLOW, Slow as Molasses W/Sweet Brown Shuga(Suger). Even with the new Radeon 3XX series, 8k resolution with maxed out settings? I think even with three of them at full scaling speed, will still have a hard time, But this is just my own opinion. I would love to see 8k benches with that card, sorrie for being off topic here.