City of heroes eating up CPU space like it's going out of style.

I've had this problem before, but then it went away, but now it's back again. When I play city of heroes, it'll soon eat up all my CPU space and it's not uncommon for me to see 98-99% CPU usage. It hasn't done this for a good few months, but it recently started up.

---System information gathered by CoH Helper version 0.2.0.2---

DxDiag gathered at May 12, 2012 04:01 (-04:00)
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.120330-1504)
System Manufacturer: Dell Inc.
System Model: Studio XPS 1645
BIOS: Ver 1.00 BIOS A13 PARTTBL
Central Processor: Intel(R) Core(TM) i7 CPU Q 720 @ 1.60GHz (8 CPUs), ~1.6GHz
Memory: 6144MB
.Net Memory Report: 3393MB out of 6132MB available
Page File: 8873MB (3389MB currently in use)
C Drive: (ST9500420ASG) 33602MB out of 466959MB (7%) free
D Drive: (TSSTcorp DVD+-RW TS-T633C) zero-size drive
Windows directory location: C:\Windows
DirectX: DirectX 11
DirectX Diag version: 6.01.7601.17514 (64-bit version)

Display Notes: No problems found.
Sound Notes: No problems found.
Input Notes: No problems found.

Monitor:
Monitor's Max Resolution: (blank)
Video Device Name: ATI Mobility Radeon HD 4670
Manufacturer / Chip: Advanced Micro Devices, Inc. / ATI display adapter (0x9488)
Video Memory: 3825 MB
Driver Version: 8.950.0.0
Driver Date: 2/14/2012 11:17:04 PM
Driver Language: English

Sound Device Description: Speakers / Headphones (IDT High Definition Audio CODEC)
Driver File: stwrt64.sys
Driver Version: 6.10.6267.0000
Driver Date: 1/21/2010 8:10:00 AM


WMI Information
Motherboard Manufacturer: Dell Inc.
Motherboard Model: (empty)
Motherboard Product:
Motherboard Version: A13
BIOS Manufacturer: Dell Inc.
BIOS Name: Ver 1.00 BIOS A13 PARTTBL
BIOS Version: DELL - 6040000
BIOS Release: 20110401000000.000000+000


Registry Information for Current User
Resolution: 1119x833
3D Resolution: 1119x833 (Not using renderscale)
Full Screen: No
Maximized: No
Screen Position: 70, 100
Refresh Rate: 60Hz
Vertical Sync Enabled: Yes


Physics Quality: High
Maximum Particles: 50000
Max Particle Fill? 10.000
Physics Card Enabled: No


Anti-aliasing: Off
Anisotropic Filtering: 4x
Texture LOD Bias: Smooth
Water Effects: Ultra quality
Bloom: 1.000 (turned on)
Depth of Field Enabled: Yes
Desaturation Effects (Sepia) Enabled: Yes
Shader Detail: High


World Texture Level: Very High
Character Texture Level: Very High
World Detail Level (Vis_Scale): 1.000
Entity Detail Level: 1.000
Shadows Enabled: No
Shadow Mode: Unknown (4)
Shadow Map Shader: High quality
Environmental Reflections: High quality
Advanced Occlusion Settings: No
Ambient Occlusion: High quality
Occlusion Strength: Strong
Blur: Trilateral
Ambient Resolution: Quality


Gamma Correction: 1.000
Geometry Buffers (VBOs) Enabled: Yes
Suppression of FX When Camera Close Enabled: No
Close Suppression Range: 3.000
Show Advertisements: Yes

Audio Mode: Performance
3D Audio: No
FX Sound Volume: 0.105
Music Sound Volume: 0.000

Show Advanced Graphics Options: No
Overall Graphics Quality: 1.000
Reverse Mouse Buttons: No
Save Login Username: Yes
Transfer Rate: Unknown bytes/second
Current Game Version: ?
Installation Directory: C:\Program Files (x86)\NCsoft\City of Heroes

Mod files in the Data directory
No modifications found

Turn off Ambient Occlusion and probably Shadows as well. You're trying to do too much for your system to handle with the graphics. City of heroes uses the CPU a lot more than other games for graphics.
You should also turn down your physics quality(it doesn't do much past low anyway) as well as reflections and water quality. Ultra is too high for those. You're better off no higher than "high", but reflections will eat up CPU resources fast.

Edit:
FYI, ambient occlusion and shadows don't play well together sometimes. Use one or the other, not both.