Midknightprince wrote:
How can a 750ti be below a 660 ?
For GTX cards, first number is the generation. A 700 series will have more features than a 600 series, but not necessarily more speed. The last two digits are the step level of the GPU & memory. In this case, your 750 is one gen higher, but one step lower than a 660. You have more features, but roughly the same speed at the end of the day. Basically x50s are the budget end and x80s are the upper end. I always try to use x60s or x70s, they give a solid amount of power and don't break the bank.
Just putting in a new card doesn't always solve things either. It's possible to be CPU-bound or your bus speed can't cope with the newer card's throughput. I'm not a hardware specialist by a long shot so it's hard for me to make a call on that.
For
deferred rendering, multiple buffers need to be rendered at once (colour, depth, normals, etc.). This means the raw speed at which your card can pump out pixels counts for a lot. And many small overlapping chunks of light data (like in interiors) adds extra overdraw to the buffers (compared to outdoors during the day).
Before spending any money, just try the free stuff like limiting mods, lowering resolution slightly, or lowering quality level. The reason lowering resolution helps so much is because less bandwidth is needed. For example, a 1080p scene needs to push over 2x the pixels of a 720p scene. With classic assets (no mods) 720p and 1080p look almost identical.
If you're getting along OK for now, I wouldn't recommend buying a new card. I'll add some new options to scale back interiors soon, and mod creators might optimise things further in the future.
Please just keep in mind I only focus on the base game. Mods are created by community members and YMMV depending on a lot of factors.