Maybe you should consider what he/she was using to make God of War 2 look so good...
God of War 2 PAL - Gameplay 12 Emulator PCSX2 0.9.7.3062
CPU: Intel i7 920 - Watercooled @ 4Ghz OC;
MB: Asus Rampage 2 Extreme;
MEMORY: DDR3 Muskin 3x2GB @ 2000 Mhz;
HDDs: 2 x WD 750 Ent. Re3 Raid 0;
VIDEO: XFX GTX260 Black Edition;
PS: Antec TruePower Quattro 850W;
CASE: Corsair Obsidian Series 800D;
MONITOR: Samsung 22" 2232BW;
OS: Windows 7.
Also, he did comment on why it looked so good:
Quote:I used 1680x1050 internal resolution. Probably this is the reason. 
Yeah I know but I changed my resolution to 1680x1050 too and it didn't helped.
Are you using the same PCSX2 revision?
Are you also using the PAL version (not that I'd really think that part matters)?
Have you cycled through the interlacing options? Maybe you're using one that makes things a little blurry...
I am using the latest pcsx2.
What's the difference between internal resolution and output resolution ? I think I know what's wrong , I changed my internal resolution not the output one,how i can change my output resolution ?
The interlacing options are set to "None".
Internal resolution is what will make the game look better. That is what he was refering to.
Try cycling through the interlacing option during gameplay (press F5) and see if one of them looks a little cleaner.
output resolution actually refers to the window size, can be modified under "Window settings" at the GS video config, together with the aspect ratio and some other options.
Hint: if going to use fullscreen keep the resolution the same as your monitor's native resolution, the same you use in your desktop. Keep aspect ratio accordingly with the game, 4:3 for most and 16:9 for some, like FFX12 and a few others.
I solved it.
I put my internal and my output resolution to 1280x1024.But the trick was with the "Scalling".I setted it on 6x and it looks exactly like in the video but it lags on my pc too bad
.Anyway thanks a lot,i really wanted to find out how you can make the games look so good.
Can someone explain me what "Scalling" does exactly ?
It simply multiplies native resolution. 6x scaling is far greater than what he used.
BTW - When you choose to use scaling, whatever you put in for the internal resolution doesn't affect emulation anymore. It's one, or the other.