Kernel Task over 400% CPU usage

Question

Hello, I have some questions about the Kernel Task in my activity monitor.
Recently, after a hard disk failure, I have my Macbook Pro wiped and start afresh with Mavericks. All was well, but it slowed down tremendously in the last couple of days. I checked the activity monitor and Kernel Task is always around 400-470%, sometimes it even peaked to 1000+%! I closed all my applications but it is still taking up all my RAM. I cannot work when it is freezing up every 2 seconds. What is the problem?
Here is the report, if it helps:
EtreCheck version: 1.9.12 (48)
Report generated 3 August 2014 12:38:14 BST
Hardware Information:
  MacBook Pro (13-inch, Early 2011) (Verified)
  MacBook Pro - model: MacBookPro8,1
  1 2.7 GHz Intel Core i7 CPU: 2 cores
  4 GB RAM
Video Information:
  Intel HD Graphics 3000 - VRAM: 384 MB
  Color LCD 1280 x 800
System Software:
  OS X 10.9.4 (13E28) - Uptime: 1 day 8:2:57
Disk Information:
  WDC WD5000LPVX-00V0TT0 disk0 : (500.11 GB)
  EFI (disk0s1) <not mounted>: 209.7 MB
  Macintosh HD (disk0s2) / [Startup]: 499.25 GB (121.06 GB free)
  Recovery HD (disk0s3) <not mounted>: 650 MB
  HL-DT-ST DVDRW  GS31N 
USB Information:
  Apple Computer, Inc. IR Receiver
  Apple Inc. FaceTime HD Camera (Built-in)
  Apple Inc. Apple Internal Keyboard / Trackpad
  Apple Inc. BRCM2070 Hub
  Apple Inc. Bluetooth USB Host Controller
Thunderbolt Information:
  Apple Inc. thunderbolt_bus
Gatekeeper:
  Anywhere
Kernel Extensions:
  [not loaded] com.m-audio.driver.firewire.dice (2.4.2 - SDK 10.6) Support
Launch Daemons:
  [loaded] com.adobe.fpsaud.plist Support
Launch Agents:
  [running] com.maudio.profire.helper.plist Support
User Launch Agents:
  [loaded] com.google.keystone.agent.plist Support
User Login Items:
  iTunesHelper
  Google Drive
Internet Plug-ins:
  FlashPlayer-10.6: Version: 14.0.0.145 - SDK 10.6 Support
  Flash Player: Version: 14.0.0.145 - SDK 10.6 Support
  QuickTime Plugin: Version: 7.7.3
  JavaAppletPlugin: Version: 14.9.0 - SDK 10.7 Check version
  Default Browser: Version: 537 - SDK 10.9
Safari Extensions:
  Searchme: Version: 1.3
Audio Plug-ins:
  BluetoothAudioPlugIn: Version: 1.0 - SDK 10.9
  AirPlay: Version: 2.0 - SDK 10.9
  AppleAVBAudio: Version: 203.2 - SDK 10.9
  iSightAudio: Version: 7.7.3 - SDK 10.9
iTunes Plug-ins:
  Quartz Composer Visualizer: Version: 1.4 - SDK 10.9
3rd Party Preference Panes:
  Flash Player  Support
  PreferencesPane  Support
Time Machine:
  Time Machine not configured!
Top Processes by CPU:
      11% Disk Utility
      11% repair_packages
      7% helpd
      5% WindowServer
      3% hidd
Top Processes by Memory:
  233 MB Finder
  66 MB mds_stores
  49 MB WindowServer
  37 MB mds
  34 MB Disk Utility
Virtual Memory Information:
  1.22 GB Free RAM
  1.35 GB Active RAM
  394 MB Inactive RAM
  1017 MB Wired RAM
  1.50 GB Page-ins
  100 MB Page-outs

Answer 1

The kernel is using excessive processor cycles. Below are some possible causes for the condition.
Throttling
When it gets high temperature readings from the hardware, or a low-voltage reading from the battery, the kernel may try to compensate by interrupting the processor(s) to slow them down and reduce power consumption. This condition can be due to:
☞ a buildup of dust on the logic board
☞ high ambient temperature
☞ a worn-out or faulty battery in a portable
☞ the malfunction of a cooling fan, a temperature sensor, a voltage sensor, or some other internal component
Note that if the problem is caused by a sensor, there may be no actual overheating or undervoltage.
If the computer is portable, test with and without the AC adapter connected. If kernel_task hogs the processor only on battery power, the fault is in the battery or the logic board. If it happens only on AC power, charging is causing the machine to heat up. That may be normal on some models. CPU usage should drop when charging is complete.
Apple Diagnostics or the Apple Hardware Test, though not very reliable, is sometimes able to detect a fault. For more thorough hardware testing, make a "Genius" appointment at an Apple Store, or go to another authorized service provider.
If nothing is wrong with the hardware, then whatever you can do to improve cooling may help.
Installed software
User-installed software that includes a device driver or other kernel code may thrash the kernel. That category includes virtualization software, such as Parallels and VMware, as well as most commercial "anti-virus" products. Some system-monitoring applications, such as "iStat," can also contribute to the problem. You can test for this possibility by completely disabling or removing the software according to the developer's instructions, or starting in safe mode. Note, however, that disabling a system modification without removing it or testing in safe mode may not be as easy as you think.
Corrupt NVRAM or SMC data
Sometimes the problem is cleared up by resetting the NVRAM or the SMC.
External display
Connecting an external LCD display to some MacBook Pro models while the lid is open may cause this issue. If applicable, test by closing the lid or disconnecting the display. You might get better results with a newer LED display.