Help, DBZ BT3 "Clearing cache mode"

[Mathimanya]

Hi, what's up guys?
Look i have a "problem", i play DBZ BT3 perfectly but the speed is not so good (23fps generally) in fight, and 60fps in menu. But when i fight something happens "clearing cache mode" is activated sometimes not always and FPS increase to 30FPS, the speed is great.
So why i cant activated "clearing coche mode" always? and my computer could support more fps with a better configuration? in that case, wich?

My computer
Operating System: Windows 7
Processor/CPU: AMD Athlon II X4 640 3.01Ghz
Video Card/GPU: Geforce GT440
Memory/RAM: 3Gb
Dolphin Revision Currently Using: 3.0-716 32 bit
Thank you guys
PD: I speak Spanish, and my english is basic, sorry for that

[Squall Leonhart]

This game, on both the Wii and PS2 are Geometry heavy
On the consoles, Geometry doesn't have to batch its way through an api that depends heavily on the CPU for execution
Your cpu is the cause of the slowdowns, code cache clearing has nothing to do with the performance, the difference each level has in regards to how much backgrounds geometry is present does.