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[VIDEO] CPU Performance vs. Real-Time Performance in Your DAW


Senior Member
And to the hardware purists out there - someone pointed out that EFI is used in place of BIOS these days. Yes, it is - but I'll probably be calling it BIOS for a long time to come :)
If you want to be really particular it is UEFI or (uEFI) Unified Extensible Firmware Interface) and yes I am sad enough to know that off-by-heart :/

For Macs until recently (I believe they now use the full specification) Apple only used custom-EFI, as they were only utilizing a substrate of the EFI standard

I do understand however that with Windows 8 they began to implement more and as of the release of Windows 10 they use the full spec to support Secure Boot for Windows with Bootcamp

Sad techy here, who lives in the basement ;)


Active Member
What an awesome video Richard!
Thanks for making this subject clear enough for thick headed guys like me to understand!


New Member
Still the best information on the subject !!! I saw the videos on youtube in the past, but want to thank the author again for the insight.

Unfortunately, in real life - unless you have the budget / time (or technician) to experiment - it's not so easy to implement.
1) You can't base serious decisions on specs only - that is if you (can) have real specs of all the subassemblies/parts and how they're integrated
2) Products are (dis)appearing continuously, and manufacturers change part sourcing / implementation during product lifecycles, etc.

The monitoring tools are a help - unfortunately windows-only afaik :(

BTW : willing to pay for a OS X realtime monitoring tool similar those mentioned in the article/videos !!


Senior Member
One of the best technical explanation videos I have ever seen! Hope the author will make more on other topics.

Regarding OS X macs, its important to understand that OS X uses an entirely different mechanism to handle low level drivers then windows. Windows uses something called Deferred Procedural Call (i.e., DPC), and it has to do with the fact that Windows operating system is interrupt driven. There are pros and cons to being interrupt driven, but one of the cons is this symptom called DPC latency. OS X does not use that mechanism at all. I'm not exactly sure right now what OS X does do, but it does not do DPC. So there is no point to worrying about whether your mac has high or low DPC latency since we don't have a DPC latency checker utility..its not relevant. There is no such thing as DPC in OSX. OS X works a little differently.

That being said... There actually is a built in command line utility in OS X for monitoring latencies... when I run it, they are all low enough to not cause any concerns...so I don't know what OS X is doing differently, but knock yourselves out..its called /usr/bin/latency. From the command line you can type 'man latency' to read more about it.

Much of this video is still extremely good information for musicians, regardless of whether you're using OS X or Windows, in terms of understanding that neither computer is an actual real time computer. It operates on buffers and gives an illusion of real time operation, with buffer latency in the sound card being the thing that enables that to happen. We make music in real time, but the computer is processing things and timesharing different components of the system. Very well presented video here and applicable to both platforms, except for the DPC section.
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