Resident Evil 4 On ATI Mobility Radeon HD 5730

Hey guys, can you help to understand why re4 is so taxing on my system with following mods: the ultimate community patch, hi poly Leon(1024 res I believe)enhanced wood and barrels(It goes to 25fps and lower with these sometimes alone.) With enb series activated plus 8xaa and af it is like playing a slideshow!
Here are my pc specs- alienware m15x laptop with i7 2.8ghz cpu,6 gb ram, 320 gb hdd, ati mobility radeon hd 5730. Also, my comp. hdd is defragged. I use game booster too. I can run fallout 3 after optimizing it with tweakguides wirh a bunch of mods full NMC texture pack and get 60fps(of course sometimes dips to 19fps when loading textures.) Now I think we can all pretty much agree that fallout 3 is probably head and shoulders above re4 pc with the technology implemented in it-far more beautiful game without mods. Thanks guys.
System requirements For Resident Evil 4-
Minimum Recommended
Windows
Operating system Windows 2000
CPU 1 GHz Intel Pentium III or AMD Athlon 2 GHz Intel Pentium 4 or AMD Athlon XP
Memory 256 MB RAM 512 MB RAM
Hard drive space 7 GB free hard disk space (full install only)
Graphics hardware NVIDIA GeForce 6200 128 MB or ATi Radeon X1300 128 MB NVIDIA GeForce 6200 256 MB or ATi Radeon X1300