Universal asio driver For wdm audio Instruction Manual

6. Hardware Buffer on/off 

Note: For WaveRT drivers (Vista), this box is labeled “

Note: For WaveRT drivers (Vista), this box is labeled “

Allow Pull Mode (WaveRT)

Allow Pull Mode (WaveRT)

” instead!

” instead!

Enables the hardware buffer for the highlighted device. This only works for so called “WavePCI” 

miniports, as other types of WDM drivers do not usually allow direct access to the hardware buffer.

Adjustment for best hardware buffer performance involves the “ASIO Buffer Size” slider and the “Buffer 

Offset” slider (see below). Hardware buffering works best for rather small ASIO buffer sizes. Try 

something between 128 and 256 samples as a starter!

The biggest advantage of using the hardware buffer is that this method uses a lot less CPU. In addition, it 

may be possible to decrease latencies even further.

In multi-device-setups, it is possible to mix Hardware-buffered devices with devices that are not. This, 

however, is not particularly recommended!

If hardware buffering is not supported by a particular audio device, there will be an additional latency of a 

couple hundred milliseconds, which is clearly audible.

“Allow Pull Mode (WaveRT)”

There are two basic access methods for a WaveRT device, “pull-mode” (also called “event-mode”) and 

“push-mode” (also called “polling mode”). “push-mode” is thought to be supported by all WaveRT 

drivers and (Vista) OS platforms, whereas “pull-mode” wasn't even officially documented by Microsoft 

until almost one year after Vista went RTM. As a consequence, “pull-mode” is still broken in a number 

of instances.

If this box is left unchecked, ASIO4ALL will never use “pull-mode”, otherwise it will use it whenever 

possible. If it works, “pull-mode” provides tighter timing and is generally thought to be technically better 

than “push-mode”.

Note: The old ASIO4ALL 2.8 behavior for this option was as if 

Note: The old ASIO4ALL 2.8 behavior for this option was as if