Well, this is a topic that requires patience on top of all. We're already studying a bunch of alternatives to improve JPCSP's performance without breaking the code too much, but the main priorities now still need to be simple and efficient.
I haven't looked at PCSX2, but I suspect the reason behind that frame rate gain is because of the FBO (or any equivalent custom method they're using for offscreen rendering) size. When changing the size, the FBO's internal size is probably also changed to save up processing resources, and that's why you see the frame rate gain.
As for filters, that's something that I'm already studying, but like Orphis stated, it's still not a priority. After we complete a few more goals in rendering and fix a few bugs, we'll obviously start adding them, so the screen will finally stop looking like a big mess of huge blocks in full screen mode.
I haven't looked at PCSX2, but I suspect the reason behind that frame rate gain is because of the FBO (or any equivalent custom method they're using for offscreen rendering) size. When changing the size, the FBO's internal size is probably also changed to save up processing resources, and that's why you see the frame rate gain.
As for filters, that's something that I'm already studying, but like Orphis stated, it's still not a priority. After we complete a few more goals in rendering and fix a few bugs, we'll obviously start adding them, so the screen will finally stop looking like a big mess of huge blocks in full screen mode.