What's your DPC latency?

Hi!

I'm considering a T400 as my first notebook but need reasonable DPC latencies (for audio recording).

If you have a T400 (or T500 or similar ThinkPad), would you run the DPC Latency Checker and post the results? Just a description of "mostly green," "mostly yellow," or "mostly red" would be cool. A screenshot would be wonderful if you can. Please mention your model (T400, T500, etc.) and OS.

Thanks!


Background Info

I'm a music student trying to find a durable 14" notebook. The Dell Latitude E6400 is was my other choice, but [THREAD=297054]it's currently plagued with DPC latency problems[/THREAD]. I'm planning to use an external audio interface for recording (USB or Firewire).

High DPC (deferred procedure call) latencies are often the culprit of hiccups in audio or video playback. For audio recording, they are deadly—which is why I'm curious about the T400's latencies.

 

absolute max at 1027us with this browser open. mostly green with a few yellows. no red

 

I know you asked about the T400, but I will report my specs for the x200 Tablet so other people have that information.

Vast majority is green ( ≈400µs)
Absolute maximum (1 yellow spike per interval) of 1864 µs

Conclusion "This machine should be able to handle real-time streaming of audio and/or video data without drop-outs."

General system information - x200 Tablet, 1.86GHz, Vista Business 64, Outlook & Firefox in background, 320GB 5400RPM drive (w/ Truecrypt).

 

Thanks! I appreciate it. It will be interesting to see what the responses are across different ThinkPads, T400 or otherwise.

 

*Bump*

Anyone else (T400 especially)? It'd be great to get a few more scores! (It takes only seconds to run the test. )

Is anyone averaging 500 μs or less?

 

I have a T61 that I play VSTs on all the time. No DPC Latency issues, mostly green with very occasional yellow spike. Thinkpads are pretty great for realtime/live audio performance given that you are using a decent external audio interface.

EDIT: I've really only experienced DPC Latency issues on PCs with Atheros wireless cards. Their drivers seem to spike the DPC into red pretty often.

 

My max was 967. Most were under 400. This is with FF, Thunderbirds, steam, pidgin, and a defrag app running.

 

OK, so now I can vote in my own poll. My T400 arrived. Upon running the DPC Latency Checker, I saw latencies consistently in the red range, above 8 ms. After some trial and error, I traced the problem to the Optiarc DVD+-RW drive that shipped with my machine. Disabling the device gives me latencies well into the green, generally under 300 μs. There are only occasional spikes in the 1000 μs range (every 15 s or so—sometimes green, other times yellow). I'll do some more trial and error later to see if I can find the culprit of these small spikes, but they are still within an acceptable range.

Overall, I'm happy. I am fairly confident that this system will be suitable for some recording with an external audio interface.

 

Here are the results of my test:



X200, Vista Home Premium, P8400, Samsung SLC 64gb SSD.

 

T400 with Vista 32 Business SP1 fully updated running with ATI graphics and WiFi on.

 

I'm running Windows7 on a T61 with a T7500 and 4GB of RAM.
Not the model you requested but here it is for comparison...