Parallel Parking CPUs or is it Parking Parallel CPUs?

Recently, a large audit required the use of a spare laptop to help with the scanning. We decided to use a quad-core laptop because CPU utilization is one of the bottlenecks for our LanGuard scans. While prepping the laptop, I wanted to make sure the quad cores were being utilized, but instead found out that two of the cores were “parked” and sitting idle. It turns out this is a feature built into Windows in order to conserve power and extend battery life. Windows can dynamically park CPUs when the system load is light and bring them back on line when the system load increases. If you have a quad-core processor, you can test this by opening Resource Monitor (open Task Manager, go to the Performance tab, click on the Resource Monitor button), clicking on the CPU tab, and looking at the individual cores on right hand side of the screen. If you don’t have anything running, you should see one or two cores go into a “parked” state and be greyed out. As you open applications, they will be reactivated. The feature also works with dual-core CPUs, but the system load doesn’t have to be as high to bring both cores online. [more]
 
During the audit we were preparing for, performance was much more of a concern than battery life, so I wanted all four cores to be active all the time. To accomplish this, you have to edit the registry using the following steps:

  • Open regedit and search for  0cc5b647-c1df-4637-891a-dec35c318583
  • Everywhere you find that key (there will likely be more than one instance), change the ValueMin and ValueMax keys to ‘0’
  • Reboot the system

General CPU. LanGuard Windows 7