How To: Improve Windows Vista Network Performance, While Running Multimedia Programs
Fact: Windows Vista is throttling down the network interface to 10 packets per second to prevent choppy audio playback.
Reason: Users expect multimedia applications, including music and video players, to offer a seamless playback experience. However, demand for the CPU by other concurrently running applications, like antivirus, content indexing, or even the mail client, can result in unpleasant hiccups. To provide a better playback experience, Windows Vista introduces MMCSS to manage the CPU priorities of multimedia threads.The Multimedia Class Scheduler service (MMCSS) enables multimedia applications to ensure that their time-sensitive processing receives prioritized access to CPU resources. This service enables multimedia applications to utilize as much of the CPU as possible without denying CPU resources to lower-priority applications.
This is supposed to help with multimedia performance but of course it is very counterproductive when your audio/video files are streamed over the network.
In circumstances where you experience a decrease in network performance, you can control the throttling rate to improve network performance in Windows Vista.For this, configure a registry key NetworkThrottlingIndex to control the throttling rate.But do it careful and with caution as it may affect the multimedia playback quality.
- Make sure that you have installed Windows Vista SP1.
- Start the Windows Vista registry editor by clicking Start, then, Run, and then entering regedit.
- You’ll need to provide administrative confirmation if User Account Control(UAC) is turned on(If you are using Windows Vista).
- Navigate to the following registry key:
Name : NetworkThrottlingIndex
Value type : DWORD
Value data : From integer 1 through integer 70 (Decimal) (Decimal)
- By default, the value for the NetworkThrottlingIndex registry entry is set to 10.For better performance,you can try the values 50 to 70.
- Restart the Multimedia Class Scheduler service (MMCSS).
- If you get skipping in your audio or video while doing network transfers, you might need to lower the value.
To turn MMCSS off without mucking with the service dependencies, just set the SystemResponsiveness regkey to 100. If things start skipping on you, then you might have to turn it back on.
Note that when the NetworkThrottlingIndex registry entry does not exist, the behavior resembles the default behavior.Also this settings are only really useful if you are on a gigabit network – the default values should be fine for a Wireless network.