All emulators are CPU intensive. And all of them use either 2 cores or 3 cores of the processor. However the framerate is directly proportional to the clock speed of the processor, and scales very well. I see you have an unlocked processor. You can try and overclock if you are comfortable with overclocking, because that will surely give a huge boost to the framerate.
There is a custom resolution option in PCSX2 that will allow you to set whatever resolution you want to render the game at. But I am not sure how well it works, since I've only played at 1080p.
The problem with PS2 emulation is that the scene isn't prospering as well as the Wii emulation scene. There are some software limitations that will limit you to certain framerates no matter how amazing your processor is.
There is a custom resolution option in PCSX2 that will allow you to set whatever resolution you want to render the game at. But I am not sure how well it works, since I've only played at 1080p.
The problem with PS2 emulation is that the scene isn't prospering as well as the Wii emulation scene. There are some software limitations that will limit you to certain framerates no matter how amazing your processor is.