Say I have an external sound card, like M-Audio M-Track, and I have connected it to my PC. Knowing the RAM value for my pc, how can I calculate what latency i will get, in terms of milliseconds?

What factors does it depend on ?

  • What sort of latency you are talking about? The audio monitoring latency? Because Ram, USB and Hard drives has little to do with this.
    – Izhaki
    Sep 13, 2013 at 1:24

3 Answers 3


The best bet is to try it. It depends on too many factors such as the quality of your USB ports, the speed of your processor, the architecture of your motherboard, the speed of your ram and hard disks, the software you are using, how clean your OS is, etc. There is lots you can tweak, but you aren't really going to be able to estimate latency without trying it and seeing what you can get and then troubleshooting any problems that are causing slow downs.

  • Thanks AJ! But I will buy a sound card online and I don't think I have the chance to try. Isn't there a way to estimate it with assumptions like OS is clean, hard disks are empty, there are no running programs etc ?
    – Cengiz Frostclaw
    Sep 12, 2013 at 22:16
  • @CengizFrostclaw - It's going to depend on what you are doing and how fast your computer is and if the particular effects can be processed on the card itself. With cards with built in processors, you should be able to tell what the latency is as it shouldn't depend on the computer. But if it needs to pull in audio and needs to do processing on the CPU, it's really too complex to judge. It's kind of like estimating fuel efficiency. It might not even always be the same in the same situation. Assuming your computer is decent though you should get approximately what the card estimates.
    – AJ Henderson
    Sep 12, 2013 at 22:37
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    I'd recommend buying from someplace with a return policy that you can use if you have problems as well. It's just good practice with any specialized hardware really.
    – AJ Henderson
    Sep 12, 2013 at 22:38

If the OS you are using is Windows

The most important factor in latency reduction is ASIO drivers which should be supported by your external sound card. Simple, non-professional\built-in sound cards, use Microsoft DirectSound interface between applications and the sound card. ASIO drivers can bypass the normal path between Windows OS and the sound card so that the application connects directly to sound card hardware.

Yes, your PC peripherals are important factor as well, but I don't think you should be worried too much by the general latency performance.

  • 1
    Whether one should be concerned with the latency depends heavily on the application. Windows sound server is of course unusable for pretty much everything, but even with ASIO driver you often can't get it fast enough, for instance when using VST effects for live monitoring. Oct 13, 2013 at 17:30

You set the latency, although there is a default. It depends on the card or interface, however, it generally will always have a good range of values. My computer's soundcard's buffer size can't be set as high as my interface's (layla24), which actually can be a problem. It's in the drivers, however, so you'd have to check into drivers to know exactly the maximum buffer setting.

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