Zelda SS - Skip EFB acess from CPU

[ygorvaz]

Well, hello everyone, I'm here to discuss about Zelda Skyward sword.
No, I'm not here to make questions about "how can I make dolphin run faster on my PC", I'm just here to know a little more about a problem.
Well, the thing is. I started playing Zelda Skyward sword, searched a little in the dolphin's wiki to know the best settings, etc etc. Then there is this option, "Skip EFB acess from CPU", which was being described as "If marked will cause problems while trying to aim correctly". Well, no big deal, let it unchecked and everything is fine.
But then I started playing. I have a somehow weak CPU, Core 2 Quad 2,6Ghz which the Intel shitty motherboard doesn't let me overclock, a very weak GPU, GeForce 9400 GT. Okay, I got 80% speed in open areas. I wasn't expecting a full speed from the start, since I was just testing, I'll buy a new CPU next month.
So, after playing a little, I decided change some options to see what I could do to make the game run a little faster. And after sometime I decided to see what could happen if I checked the "Skip EFB acess from CPU". My surprise was when the game went from 60% to full speed. Not only that, but the aim system was somehow okay which was strange. "Maybe I'm lucky", I thought.
Well, not exactly. The aim system is okay when you're just looking around, but when you're with some item like the slingshot Link will just fail to shoot where you're aiming.

So, the whole thing is, someone know what causes this error? Can it be fixed? I'll change my PC next month so I don't really care, but I would like to know a little more about it.

EDIT: Okay, explaing why I created this thread.
Look what happens when I try to shoot with "Skip EFB acess from CPU" checked:
http://img220.imageshack.us/img220/5572/linkbeingaidiot.png
Now imagine that it happens to everybody (not the problem itself, but the way that link shoots: a little more to the up and right), then we could create a patch to fix it. So, for the people who have skyward sword, what happens when you try to shoot with "Skip EFB acess from CPU"cheked?

[neobrain]

Uh, you sound like you answered your own question without noticing it?

[ygorvaz]

(04-23-2012, 04:35 AM)neobrain Wrote: Uh, you sound like you answered your own question without noticing it?

Yo, I'm not waiting about a answer like "Just disable the Skip EFB acess to CPU option", I know it would fix the problem, but I want to know what happens to cause the problem, so, we could fix it or create a patch.
In my case, Link doesn't shoot to a random location, he shoots so something like a little more up and right.
Now imagine, if it happens to everybody, like, when everybody tries to shoot then Link shoot to someplace more up and right from where you were aiming, then we could make a patch to correct it a little. It would be interesting for people with a weak cpu (like mine) so they could gain a little more speed enabling "Skip EFB acess to CPU"

[Squall Leonhart]

The game uses Framebuffer readbacks to tell where the current target is (i assume)