To record with lower latency, work with more plug-ins or to resolve problems with an audio PC, streamline Windows with the steps below.

Drivers

Install the driver for your audio interface. Install the latest version of the driver, which is downloadable from the manufacturer’s website. Ignore a driver installation disk that comes with the interface since it’s likely outdated. Make sure that the driver you install from the website is designed for your version of Windows (ie: Windows 7 32-bit, Windows 8.1 64-bit, etc.).

It’s recommended to use an audio interface that works with the ASIO driver mode. Interfaces that are class-compliant or use the generic ASIO4All driver are subject to high latency.

Uninstall unneeded drivers and disable unneeded hardware. Drivers that are no longer in use (like the driver for an old audio interface) can be uninstalled from Control Panel > Programs and Features or the Device Manager. In the Device Manager, open the View menu and select Show hidden devices to display any hardware that isn’t connected to the computer. Right-click and select Uninstall to remove it. In some cases, Windows installs the same device multiple times and obvious duplicates can also be uninstalled.
Devices that are completely unused (such as an HDMI audio port on a graphics card that’s not connected to a display or a floppy disk drive) can be disabled from the Device Manager. Be very careful when disabling and uninstalling devices since doing so will make them unavailable in Windows.

Since each driver requires processing time from the CPU, culling installed drivers can improve audio latency. Efficient drivers may only need a fraction of CPU time, but when several drivers are running, that fraction adds up. Inefficient drivers, however, can require large amounts of CPU time, which delays other drivers from being processed. If an audio interface driver is waiting behind either of these cases, audio latency will increase.

Update system drivers. Drivers for other computer components like the graphics card and motherboard chipset should be current. Check with the manufacturers’ websites for the latest drivers.

Note that if drivers are missing or installed incorrectly, Windows and all other software will be unable to communicate properly with your hardware and performance will be degraded.

Windows Optimizations

Set Windows Power Options to High Performance. Find this setting in the Control Panel > System and Security > Power Options. This will set the CPU and other components of the computer to operate at the maximum.

Disable power management for USB root hubs in the Device Manager. Open the Device Manager and expand the Universal Serial Bus controllers category. Right-click each USB Root Hub, click Properties and click the Power Management tab. Uncheck any boxes next to “Allow the computer to turn off this device to save power.”

Disable startup items. Programs that start up with the computer continue to run in the background and consume resources that could be used for audio production. Disabling them speeds up boot time and the computer in general.
To disable startup items on Windows 7, hold the Windows + R keys at the same time to open the Run prompt. Type msconfig then click [OK] to open the System Configuration utility. Go to the Startup tab and disable anything that's not necessary. Leave anything for graphics hardware and the audio interface checked.
On Windows 8/8.1, open the Task Manager and go to the Startup tab to disable these items.

Disable automatic Windows Updates. It’s important to keep Windows current, but when updates download and install by themselves, they can slow down and interrupt other things that you’re doing (like mixing or recording). Open Control Panel > System and Security > Windows Update > Change Settings and set it to Check for updates but let me choose whether to download or install them.

Exclude audio drives from search indexing. Automatic search indexing causes extra hard drive activity while the index is built, potentially causing error messages and dropouts. Open Control Panel > Indexing Options and click [Modify] to remove your audio drive(s) from the Indexed Locations. Note that new files on excluded drives will not appear in search results and this recommendation does not apply to computers with a single hard drive.

Use a non-intrusive antivirus. Many antivirus programs can conflict with audio software due to resource demands. Microsoft Security Essentials, AVG or Malwarebytes are recommended due to their low CPU usage. However, disable them during performance-based tasks if their file scans cause overly heavy disk usage.

If you require higher security settings, consider disconnecting from the Internet to safely disable antivirus while using audio software, using a separate computer for audio production or modifying your browsing habits.

Disable Wi-Fi and Bluetooth when they’re not in use. Wireless and bluetooth hardware can interrupt the CPU from processing audio. Turn these off if you’re not using them, especially if dropout messages are present.

BIOS/UEFI Tweaks

Disable processor throttling and dynamic frequency scaling. Not every motherboard BIOS or UEFI will have this option, but when available, disable Enhanced Intel SpeedStep (EIST), Intel Turbo Boost, AMD Cool ‘n’ Quiet or AMD Turbo Core. This will set the processor to always run at its maximum so your DAW has as much power as it needs.

Disable processor C states. When a processor enters a C state, it moves to a reduced-power mode. Disabling this setting in the BIOS/UEFI will prevent the CPU from idling and keep it running at its maximum at all times.

Note that disabling these settings will result in higher operating temperatures and reduced laptop battery life.