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spacecadet
Posts: 23
Registered: ‎11-12-2008
Location: New York
0

Horrendous DPC latency?

I was hoping I could use my SL500 to record music with, but not only does it look like I'm outta luck, it looks like I'm not even in the ballpark.  Take a look at this screenshot from DPC Latency Checker 1.1:

 

http://i88.photobucket.com/albums/k176/badasscat/latency-1.jpg

 

10,000us!!!   On my desktop, I get around 2-3us.  The odd thing is these aren't spikes, either - it is consistently at 10,000us.

 

I have tried disabling everything I can think to disable, and nothing has worked.  The other strange thing is that when the hard drive is in use, the latency drops.  On other computers I've owned, the opposite has always been true.

 

Has anyone else had this problem?  This is hugely frustrating for me.  I mean if I can't get it flatlining in the green, then whatever... but this looks like there's something really wrong.

 

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trikka
Posts: 50
Registered: ‎09-21-2008
Location: Australia
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Re: Horrendous DPC latency?

This is from my SL400 running XP:

 

http://img89.imageshack.us/my.php?image=clipboard01mu9.png

 

Pretty much stayed that way in the few minutes I ran it, whether the system was idle, running rthdribl (stresses CPU and GPU) or HD Tach. Only had a few instances of a red bar.

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spacecadet
Posts: 23
Registered: ‎11-12-2008
Location: New York
0

Re: Horrendous DPC latency?

Was XP pre-installed on your SL400 or did you install it clean?  I'm just wondering if it's something Lenovo installed along with Vista rather than Vista itself.

 

I might try installing XP as a dual boot, if that's even possible.

 

802.11n
Xeogin
Posts: 183
Registered: ‎08-21-2008
Location: United States
0

Re: Horrendous DPC latency?

[ Edited ]

I'm using the Vista Business Lenovo installed on my SL500, and I'm getting about 130µs with some 1000µs jumps, and as I was typing this I got a full red bar jump up outta the blue.

 

Wish I knew more about what this thing did.

Message Edited by Xeogin on 11-16-2008 08:03 PM
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Currently Just passed the CompTIA A+ 601 with flying colours! =D
Owner of an SL500 running Vista Business with 4GB of PC2 6400 RAM
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XPenetrator
Posts: 13
Registered: ‎11-17-2008
Location: Germany
0

Re: Horrendous DPC latency?

[ Edited ]

Hello everybody!

 

I just had quite some trouble with a Dell Vostro 1310 with a very bad DPC behavior (not fixable design glitch) and wanted to replace it with a SL300. Glad I found this thread before ordering.

 

General explanation: 

Even a single red spike in the DPC Latency Checker may signify that the computer is unusable for realtime audio applications since it will most probably produce an audible artifact while recording. But most laptops will show at least a few spikes with the stock OS installation, they are caused by some troublemaker devices like card readers or webcams (their drivers to be precise). The most prominent latencies are usually caused by the WLAN card, which is responsible for one or more spikes in the 2000-6000µs range every minute. So with WLAN off and maybe the mentioned devices deactivated (in device manager or BIOS), the laptop should stay at least below 500µs forever.

 

@space cadet:

This looks almost like an OS/driver installation gone terribly wrong or a defective hardware component. I'd check again with a properly installed XP (DPC behavior is generally much better on XP than on Vista) if the problem persists. I've seen pics like yours on computers waking up from standby mode though.

 

@trikka

You did the right thing checking this under some load :smileyhappy: I hope that the single red bars came from the WLAN. So did you check that with WLAN on? If yes, can you please check again for 3-5 minutes with WLAN off and post the maximum latency shown?

 

@Xeogin 

Put very simply, the tool checks how long the line (DPC queue) is that a driver has to stand in before it gets served by the CPU. Your results probably mean that there's nothing wrong with the DPC behavior on the SL by design as well. (As I said, DPCs are longer on Vista and there's apparently also a little error in the Latency Checker making it look a tad worse than it is.)

 

Thanks for your help,

XPenetrator 

 

 

Message Edited by XPenetrator on 11-18-2008 12:09 AM
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spacecadet
Posts: 23
Registered: ‎11-12-2008
Location: New York
0

Re: Horrendous DPC latency?

[ Edited ]

Ugh, well I have my brand new SL500 in for an unrelated repair right now (I'm starting to lose confidence in these computers), I hope I don't need to send it back again for this.  I'll see what happens when I get it back; maybe it'll be magically fixed.  I have a feeling my other problem - a "bulge" under the palm rest and keyboard - was caused by something either not being seated properly under there, or a cable being tangled up or something like that.  So hopefully it was related, but I'm not counting on it.

 

If it's still doing it, I'm going to try a fresh XP install on another partition and check that.  If *that* gives me a more normal result, then I'll know it's Vista that's the problem.  If it's still screwy on XP, then I'll know it's the hardware.

 

I wonder how to even describe this problem to a tech if it comes to that.  The guys I spoke to on the phone about my other problem were obviously just reading from a script and going through a troubleshooting tree.  I doubt they even have one for DPC latency.

 

Oh, before sending it in for the "bulge" problem, I did try figuring out if it was a wayward driver... I turned every single one I could off one by one, nothing made any difference whatsoever.

Message Edited by spacecadet on 11-18-2008 08:40 PM
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spacecadet
Posts: 23
Registered: ‎11-12-2008
Location: New York
0

Re: Horrendous DPC latency?

Ok, an update in case anyone else is experiencing this...

 

I installed XP, clean install of XP Pro SP3.  Initially had perfect latency readings - in the 20's and 30's, basically flatlining in the green on the DPC Latency Checker app.

 

Then I proceeded to install drivers and updates one by one, seeing if anything would break it.

 

First, wireless.  The XP wireless driver does indeed misbehave - I got spikes into the red lasting about 15 seconds every two minutes or so.  Also smaller spikes every 30 seconds.

 

Audio, no change.

 

Graphics, seemingly no change.

 

Then the weirdness.  In order to reinstall Vista's bootloader, I needed .net framework (to run VistaBootPro).  Downloaded .net 2.0, which required me to download Windows Genuine Advantage.  Downloaded both and installed and all still seemed fine.  Latency mostly in the green, with only the spikes from the wireless.

 

Restarted one last time (actually did it by mistake, meant to boot into Vista) and suddenly my latency's up to 2000μs, solid!

 

So one by one I went backwards and uninstalled every single thing except WGA (which can't be uninstalled), no change.  2000μs latency.

 

Sigh.  At least this is better than the 10,000μs latency I'm getting on Vista.  But I'm still clueless as to what's causing it.  It almost seems like WGA is somehow, but that can't be possible, can it?

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trikka
Posts: 50
Registered: ‎09-21-2008
Location: Australia
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Re: Horrendous DPC latency?

Something I've noticed since I got the laptop is occasional momentary distortion when listening to MP3s. Thinking I might have a corrupt file, I replay the section of track in which I heard the distortion, but it turns out to be fine.

Wonder if it's related to this problem you've raised. Just ran the latency checker again briefly and it started out as green with occasional red as before, then it suddenly went into the red for about 10 bars then yellow for 10 bars. Restarted the checker and it was back to green.

 

I'd have to test for longer to see if there's any link between the red bars and MP3 distortion - don't have the patience at the moment.

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XPenetrator
Posts: 13
Registered: ‎11-17-2008
Location: Germany
0

Re: Horrendous DPC latency?

[ Edited ]

"I installed XP, clean install of XP Pro SP3. Initially had perfect latency readings - in the 20's and 30's, basically flatlining in the green on the DPC Latency Checker app."

 

That's a good sign. I know a certain laptop from a certain company starting with 'D' that had already spikes in that phase of installation. :smileyhappy:

 

"First, wireless. The XP wireless driver does indeed misbehave - I got spikes into the red lasting about 15 seconds every two minutes or so. Also smaller spikes every 30 seconds."

 

"Lasting 15 seconds" sounds like a long time to me. I've seen only between 1 and 5 consecutive "WLAN-spikes" so far. However, I don't know anyone who doesn't have to turn the WLAN off for audio work in an ASIO environment, so I'd say if the spikes remain relatively low and disappear when the WLAN is off, even the 15 seconds of spikes should not affect normal operation and can be ignored. I guess. 

 

"Then the weirdness. In order to reinstall Vista's bootloader, I needed .net framework (to run VistaBootPro). Downloaded .net 2.0, which required me to download Windows Genuine Advantage... [...]... It almost seems like WGA is somehow, but that can't be possible, can it?"

 

Wow. That sounds really weird. WGA is not causing any DPC trouble on my non-DAW/internet computer but I imagine it's not merely a service like all the others. I've never heard that it causes problems on a DAW though. Still sounds like "something" is not quite right on your computer. I can only recommend repeating the process but not installing DotNet, bootmanager or WGA or removing the latter as described here: http://www.wilderssecurity.com/showthread.php?t=140323. Part of configuring a DAW computer is keeping things as simple and light as possible. But still, that doesn't sound normal and you should document all your findings including screenshots, so you have something to send via email to the support.

 

And here we are right in the middle of the other problem you mentioned... "how to tell the Support"

Like you said, L1 support is most probably completely overchallenged with problems like this and you need a (much) higher level support right from the start, so you should ask for immediate "escalation". 

Message Edited by XPenetrator on 11-23-2008 08:27 PM
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XPenetrator
Posts: 13
Registered: ‎11-17-2008
Location: Germany
0

Re: Horrendous DPC latency?


trikka wrote:

Something I've noticed since I got the laptop is occasional momentary distortion when listening to MP3s. Thinking I might have a corrupt file, I replay the section of track in which I heard the distortion, but it turns out to be fine.

Wonder if it's related to this problem you've raised. Just ran the latency checker again briefly and it started out as green with occasional red as before, then it suddenly went into the red for about 10 bars then yellow for 10 bars. Restarted the checker and it was back to green.

 

I'd have to test for longer to see if there's any link between the red bars and MP3 distortion - don't have the patience at the moment.

 


Now that sounds really bad. That would be the 2nd 13" laptop for me that has problems to play music when the WLAN is on. I hope you're wrong. The other 13" - it was pretty fresh on the market as well and it took months until the first problems affecting my usage (for instance, listening to webradio) came to the public and I'll not go through this again. I'm inclined to buy something else now, even though I'm confident that Lenovo will be able to fix it, unlike the other company.