Can Process Lasso fix sound card buffer underrun issues?

Started by jeroen3, June 12, 2013, 03:29:46 PM

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I've got troubles with playing audio on both my pc's. As with some other people.
One is a Core 2 Duo E4800 (Win8x64) and on is a laptop with a Core 2 Duo T6670 (Win7x86) .
They both share two similarities:
1. Process Lasso.
2. Crucial M4 SSD.
3. Microdisaster's Windows

I've already set scheduler slice time to short/fixed for my laptop, which solved most of the undderruns.
But I cannot get it completely fixed. Especially when actually using the ssd.
I suspect a driver expects a hard disk-ish delay (as in a few milliseconds) but actually is interrupted in ssd-ish delay (say microseconds).

I do have latency issues (latencymon confirms), that is why there are problems.
But I'm not changing any hardware since the issue was not present, say, a year ago. (with ssd)
I guess somewhere between then and now an update for Windows has been released.

Maybe here is some smart genius who knows just how to tickle windows into playing seamless audio.
For example, prioritizing drivers, or reducing the NCQ on ahci?

I wish windows was more hard realtime...


Show your LatencyMon picture first, the Driver tab.
And also the Main tab.

BTW, what also you has tried? :)

PS:M4 ssd don't like laptop, so be careful about data loss.

Jeremy Collake

You should read this other recent thread:,3300.0.html

You might have some luck assigning CPU affinities for interrupt processing of specific devices.
Software Engineer. Bitsum LLC.


The Interrupt Affinity tool throws an bitmask error when only reading the settings. Something tells me not to play with these.

But, on a freshly booted desktop with Windows 8 I launched a LatencyMon. Did a bit of browsing, and opened some development suites (keil uvision, altium designer) which resulted in a few "pops" in the audio coming from iTunes. Which is configured at 24bit-44.1KHz, as is the sound driver.
Driver tab, Runtime 3:00, sorted highest time.

Since you will be asking, hey, why is USB so busy. A list of connected devices.

Jeremy Collake

The one thing I can tell you for certain is that if the cause is a hardware bus being saturated, then you won't have much luck with Process Lasso.

You aren't the first to have this trouble. There are some articles on the web about trying to get Windows to perform more like a real-time OS, mostly written by audio engineers.

It could also be a different device is issuing too many disruptive interrupts. That's why I suggested the interrupt affinity tool, so you can make sure a processor is available to handle interrupts from the audio device.
Software Engineer. Bitsum LLC.


Quote from: Support on June 15, 2013, 12:01:51 PM
a hardware bus being saturated

I've never thought of that. I thought it had something to do with a driver getting his timings wrong. And since the SSD is the only "younger" device, that should be it.
The way too fast nvidia gtx660 should not pose any trouble, I assume, since that is not present on my laptop.


Unfortunately I have not solved it yet.
Maybe Gates' law is true, and this is a consequence of it.

Jeremy Collake

You should Google for articles by audiophiles, see what they've had luck with..

I've had luck, in the past, resolving an issue similar to this - hard drive activity was causing audio static - by adjusting the PCI Latency. On some systems, you can set this in the BIOS, but that's rare these days.

There's a software tool to set it .. one I found is Here, but I'm not sure that's the one I'm thinking of.

This basically specifies the amount of time a device can hold the PCI bus before it must release it to another device.
Software Engineer. Bitsum LLC.



I really need a good rest...
Sorry for my last post, I don't read it completely.

Can I know did you tried Safe Mode?
And the GPU-Z, what is the speed of the PCI-E, PCI-E 2.0 x16? :)

And Nvidia driver also known as high DPC latency.



give details, download aida and send my a report, it could be a hardware resourse sharing.
we can reset, change plug and play detections so its fully redetected.

give data and explain whats wrong/


Ya, it is more harder to find out why, without any useful tools/information. :)


how is the hd queue length when that happend?

is a I/O problem?

there are some tools to boost the os memory usage (more cache etc)

but we must know how much I/O your app require, and who or what is interrupting the access to the data. (driver, player, AV, etc )

how much ram you have? how is the ssd cache configuration.