[Princess Garnet]

I'm not sure if this is the problem, but the Radeon HD4x00 series puts a good deal of it's load onto the CPU, and this is apparent in PCSX2, where the program itself needs the most of both cores, so you end up with one and a half cores for PCSX2, and half a core being taken by the GPU (or thereabouts for PCSX2, if I remember the graph runawayprisoner posted)

Still, I can't see it causing that sort of drop.

Is the dual core option enabled?

Try testing his video card in your system just to see?

 

[Princess Garnet]

You didn't read what I said. PCSX2 is very CPU intensive. It needs the most of two cores it can get. Therefore, it's easier to notice that when a video card dumps load onto the CPU. A member here by the name of runawayprisoner has tested the Radeon HD4850 and Radeon HD4870, and they both do this. Since PCSX2 itself needs the most of two cores, and the GPU needs a good deal of a single core, what happens? They both get starved. When paired with a quad core CPU, the bottleneck disappears. I wasn't saying anything about your card in general, or that it's "having problems", but due to both the nature of PCSX2 and the way the Radeon HD4x00 cards put alot of load onto the CPU, you're getting the bottleneck.

Also, try lowering the internal resolution if you need to. I had to have it at 1400x1050 to get full speed in that game. You may need lower (try 1024x1024) with the way the GPU drops load onto the CPU.

Edit: Aha, as I though.

 

[Princess Garnet]

Not kinda. It does. In my setup, I get almost or the same bad frame rate with DX9. DX10 is "another world" . 60 fps almost always. Only goes down when something too "extreme" is happening (namely huge ****ing lazors :V).

Since then, I don't use DX9. Never.

On my system, DirectX 9 with that game goes full speed all of the time (so long as the resolution isn't over 1400x1050), despite having a video card a good deal slower. Does the Radeon HD4x00 series have that bad of an effect on emulation for PCSX2 with dual core CPUs? I better stay away from the Radeon HD4890 I've been lightly considering then.

And what this means if I get 15% CPU usage on the GSdx windows and the FPS is 45 or 50-60% and 20-25fps

Slow CPU or?

Most likely, yes, but it's still possible it could be the video card. Make sure you try with the native resolution and/or no anti-aliasing to test. If the rates don't improve, it's the CPU, and given that you have a Pentium 4 though, I'd almost guarantee it's the CPU. I tried PCSX2 on a system nearly the same as yours, except the video card was a GeForce 6800GS instead. It wasn't good for much more than playing around. Actually playing games mostly full speed was out of the question.

 

[Princess Garnet]

A Pentium 4 won't get full speed in Final Fantasy X. I'm sure that's your problem. I tried that same game on a similar, but more powerful in regards to the GPU, system, and it was ~15FPS-20FPS average (this was a while back on an older version). Peak was slightly higher, and sometimes it dropped lower.

If a game plays at one speed at 1600x1200, and plays no faster at native resolution, the video card isn't the bottleneck, which would suggest the CPU as the next (and usually first, anyway) suspect for slowdowns in PCSX2.

If the slow speed doesn't bother you, then by all means, go for it. It still works. Just don't expect full speed outside maybe 2D games and a few exceptions.

 

[Princess Garnet]

Yes, but that's true only as a "general" statement. nVidia has better OpenGL support, and does not offload nearly as much work onto the CPU. If you have an ATi card that does decently, unless emulation is a major factor, it's not worth switching over if you already have an ATi card, unless, perhaps, it was also upgrade time anyway, but this isn't a factor enough alone to make it upgrade time if it isn't.