This comment: https://news.ycombinator.com/item?id=32710550 talks about running SD with 8GiB of VRAM and mentions needing to reduce this parameter to 1 to get it to output right.
My laptop takes about 6 seconds per iteration so it's significantly slower, but if you're willing to wait I bet you'll have a much easier time plugging more RAM into your system than adding VRAM.
This comment: https://news.ycombinator.com/item?id=32710550 talks about running SD with 8GiB of VRAM and mentions needing to reduce this parameter to 1 to get it to output right.