What you need to do is just reduce overhead wherever you can. I use a lot of 2k textures, but my CPU and RAM has more room and power to jugle it around with the help of ENBoost and SSME.
All things being equal, the video card would be fine if it was the weakest link. My system specs: Intel i3570k, Radeon HD6850 1 GB VRAM, 8 GB System RAM, Windows 7/64 bit, SanDisk 120 GB SSD, 1 TB Standard HDDĪs for mods to run on such a system, to be honest the RAM is the most worrisome followed by the CPU.
I have the same video card as you, Ghidorah but a newer Intel CPU, which makes a big difference along with 8 GB Ram.