SmartScan's GenCRCDiff process consumes much CPU and disk input/output. This is why the Core 2 Duo processor is recommended for Smart Scan Mode.

The Core 2 Duo processor has a throttling mechanism for CPU usage for GenCRCDiff, but it only works for non-hyper thread low-level machines. The default value is "60", which means that Smart Scan-related processes cannot use CPU over 60%.

Below are some data for your reference:

• For Core 2 Duo processor high-level machines, it takes 1 to 2 minutes of high CPU to generate diffs (only one core).
• For P4 2.0G non-hyper thread low-level machine, it takes 11 to 13 minutes of 60% CPU usage to generate diffs.
• For middle-level machines, the processing time to generate diffs is longer and the CPU usage is in between low-level and high-level processors.

To change the CPU limit of the Smart Scan-related process:

Option I

Adjust the value of the CPU limit.

1. Open the ..\Program Files\Trend Micro\Security Server\PCCSRV\wss folder\AU.ini file using a text editor like Notepad.
2. Look for the "CPULimit" parameter, and set the value you prefer.
    

   It is up to you to decide the amount of CPU limit that you want to allocate to SmartScan. You can set it between 30 to 60, with "60" being the recommended value. You can set it lower, but the trade-off for lower CPU usage is longer GenDiff time, which is launched hourly.
3. Save the changes.
4. Restart Trend Micro Security Server Master Service.

Option II

Disable SmartScan to switch all clients to Conventional Scan mode.