How well will Kingdom Hearts run on my rig?
OS: Windows 7 Ultimate (64 bits)
CPU: AMD Phenom II X4 955 Processor @3.20 GHz
GPU: NVIDIA GeForce GT 430 (1024 MB)
RAM: 8GB DDR3
It is known to be one of the most compatible and less intensive games on PCSX2.
I never put my Kingdom Hearts II disc back into my PS2 after I saw the so-called "keyblade". I don't bother to test any KH game on PCSX2 either. $quare €nix should have developed the KH series on the Wii instead.
Intel Core 2 Quad Q9400 | nVidia GeForce GTX 750 | 4 GiB DDR3 @ 533 Mhz | MSI G41M-P28 | Cooler Master RS-390-PMSR-A3 | Xigmatek TYR SD962 | LG Flatron W1943SE | HP KB-0316 | MotoSpeed F60
As Livy said, the game engine of that game is very well optimized and matches perfect the philosophy of PCSX2's speedhacks so even on a bad setup it will result playable speeds and good graphics.
Now in your case most possibly you can max out all of GSdX's settings and you won't notice any fps drops at all. If you want to overpush your hardware though with like resolutions over your screen's native and you experience some slowdown there is always the street of Game-speed cheat that has a precise result of frameskipping but I doubt you'd ever have such troubles with your hardware.