A question about framerate on different resolutions

[Ungeheuer]

Hi guys!
I'm planning to buy a 1080p display to replace my old 1280x1024 monitor. How much of an FPS decrease in games should I expect?
System specifications:
GPU: Sapphire R9 Dual-X 270 2 GB
CPU: Intel Core i5-4570 @ 3.2 GHz
System RAM: 8 GB
OS: Windows 7 64-bit

 

[MADVIU]

Depends on the game and the settings you're are playing at. For most this is a good setup, but don't expect to do Ultra at 60 fps.

 

[Ungeheuer]

I'm aware I won't be able to play the latest titles at 1080p at maximum settings at solid 60 FPS. But for example if I get 60-80 FPS in Far Cry 4 at very high settings at 1280x1024, how much of a decrease should I expect?