• Registered: 2007-11-05
  • Posts: 67

Topic: How can I improve the performances of my laptop?

Hello,

I have just upgraded an old black Macbook (Core 2 Duo - 2Ghz / 2GB of RAM) to Windows XP Pro SP3 and Mac OS X 10.6.2.

Initially, I tried Windows 7 Ultimate 32-bit and it worked, I could get the Fireface 400 work at 64 samples with Reaper, Max, Pure Data, Audacity, etc. It was necessary to disable the wireless network driver and to switch the user interface to "Basic" mode (the one that is similar to the full-featured Aero, but without the transparency, effects, etc).

But the performances were limited therefore I have replaced it by XP for now (the wireless network still being disabled).

Overally, this laptop works better on XP than on OSX for low latency audio applications (64 samples), but the maximum possible CPU load without getting any crackle is still far from 100%... While a friend had the same laptop on XP (SP1 or SP2) and it was really more reliable.

The DPC Latency Checker stays in the "green" zone, usually around 100 microseconds, with some occasional spikes at 500-1000 microseconds. These occasional spikes are still in the green zone, but ideally they should not occur...

I do not know if it's possible to get better performance on this laptop. Disabling as much drivers as I can (even this new, useless and unfancy "IDT Audio" thingie) does not change things. Any idea?

Thanks for your help
Best regards
-j

2 Reply by fl

  • fl
  • S/Mux specialist
  • Offline
  • From: Toronto, Ontario, Canada
  • Registered: 2007-11-12
  • Posts: 266

Re: How can I improve the performances of my laptop?

julien breval wrote:

The DPC Latency Checker stays in the "green" zone, usually around 100 microseconds, with some occasional spikes at 500-1000 microseconds. These occasional spikes are still in the green zone, but ideally they should not occur...

How frequent are the "occasional spikes"?  If they are every fifteen seconds, it's probably the AHCI Compliant Battery Monitor, which you can disable in the Device Manager.  While you're there, disable any wireless networking drivers, including Blue Tooth, and you should see some slight improvement in your DPC Latencies.  However, I wouldn't expect to see anything lower than 70 microseconds on a Mac Laptop.

Frank Lockwood
https://LockwoodARS.com
Fireface 800, Firmware 2.77
Drivers: Win10, 3.125; Mac, 3.36

fl's Website

  • Registered: 2007-11-05
  • Posts: 67

Re: How can I improve the performances of my laptop?

Do you mean the "Microsoft ACPI-Compliant Control Method Battery"? Indeed, there is no more spike since I disabled it... Thanks a lot for this tip Frank. Not sure if it improves practical performance using my sound card (I will be able to check it this evening hopefully).
I wonder what this component is, I'm going to check it on the Internet.

Best regards
-j

  • Registered: 2007-11-05
  • Posts: 67

Re: How can I improve the performances of my laptop?

Hello,

With this laptop, the DPC latency is better when running on the battery instead of the AC power:

- DPC latency, running on the battery: maximum = 70us; typical = 35us
- DPC latency, running on the AC power: maximum = 170us; typical = 100us

("us" = "microseconds" here)

The following devices are disabled: wireless network (mandatory), ACPI-Compliant Control Method Battery (removes some occasional spikes), Bluetooth (seems to help a very little), infrared receiver (I never used it anyway).

Why do the performances of this PC depend on the powering mode? And why can't I work at near-100% of the CPU when using the Fireface 400 at a 64-sample latency? It works properly with the built-in sound card using the directsound driver (but I doubt the actual, practical latency is better using the built-in sound card instead of the Fireface).
What did I miss? There must be something wrong in my configuration...

All the best
-j

  • Registered: 2007-11-05
  • Posts: 67

Re: How can I improve the performances of my laptop?

Something strange:

I downloaded "Notebook Hardware Control", and I set the CPU speed to "Max performance" for both battery and AC power.
When the PC runs on battery, NHC displays a constant CPU clock of 2GHz, which is normal (Core 2 Duo 2GHz).
But when running on AC power, the CPU clock is only 1GHz - though occasionally it switches to 2GHz for a very short time.
ACPI settings have no effect on this...

What happens???

-j