I downloaded PCSX3 and tried to run a game(it is playable in compatibility list) and it is lagging so much(fps is around 3 or 4). Also before that i tried PCSX2 and it was even worse, i watched youtube vids about fixing lag and it got a little better but it was still unplayable. My specs: Windows: Windows 10 64-Bit CPU: Intel Core i7 GPU: Nvidia GT 525M Also I usually play GTA V with mods, i've played Just Cause 3, Ghost Recon Wildlands, The Sims 4, GTA IV and PPSSPP games with good fps, too. I mean, PS2 games should not be lagging like this, they don't have better graphics and details compared to games above absolutely. (I know my GPU and CPU is outdated) I appreciate any helps with PCSX3 or other emulators to reduce this lag, or another way to experience games. (Also I know I must upgrade my computer) Thanks!
The PS2 might be old, however that does not mean its an easy console to emulate as you have found. 12+ year old hardware will just not cut it sadly. Looking at the setup guide for PCSX2 it states the minimum GPU requirements are a PassMark rating around 3000 (GeForce GTX 750) Sadly the GeForce GT 525M in your machine has a PassMark rating of: 463, so comes no where close which is why you are only seeing 3-4 fps. Best advice I can give you is to get a cheap AMD Ryzen Powered Mini PC on Ebay, these things really do run emulators well and don't really cost a lot when buying them used. Video showing a $150 HP Elitedesk 705 G4 emulating PS2 games at 60fps: