Hello there,
I need some help with MC3DER. I use the PCSX2 Version 1.0.0 (r5350) and BIOS Version Europe (v2.20)(2006-02-10)[SCPH-77008].

My system specs are: Windows 7 Professional 64-Bit (SP1); Intel Core-2-Quad Q8200 @ 2.33 GHz 2.33 GHz; 8,00 GB RAM; Nvidia GeForce GTS 450 (Gigabyte Edition).

Plug-ins used: GSdx 5334 SSSE3 [Renderer: Direct3D 11 Hardware, No interlacing, native PS2 resolution, no shade boost, No software mode settings enabled, hardware mode settings: everthing disabled but texture filtering is half enabled (blue square)], SPU2-X r5324 2.0.0 (default settings)

EE: Recompiler IOP: Recompiler Rounding: Chop/Zero Clampingmode: Normal
VU0: microVU Recompiler VU1: microVU Recompiler Rounding: Chop/Zero Clampingmode: Normal

EE timing hack (game fix), tried it with speedhack preset 2 safe (faster) and custom settings: INTC Loophack, recognizing loops, mVU Flag Hack, EE Cyclerate 1 and after that 2, tried it without speedhacks and no game fixes.

The game runs in slow motion and I got about 40 to 50 FPS in main menu but only 15-30 in the garage or open world racing and the sound is like slow motion too.

Think about overclocking to 2.8-3.0 ghz of you can.
2.3 ghz is low for racing games.