Dell Latitude DPC Latency Issues

I am also wondering this. I was planning on purchasing a E6410 in about a month until I saw this thread.

 

I'd be surprised, nay, shocked, should the new E6x10s fare well from the DPC latency perspective. Screw Dell and its substandard crap. I had high hopes about the Precision line until I found out they aren't any better.

 

My Latitude D820 have the slow DPC build up shown below, which repeats every minute or so. It's the DVD R/W driver. When I disable it the DPC is never above 800µS and generally around 100µS.

So the culprit was the DV-ROM driver made by "Toshiba Samsung Storage Technology Corporation". I have the latest version. One may wonder how is it is even possible to write such a dysfunctional driver, ruining the DPC while doing nothing.

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Optical drives do not use a specific driver.

It is more likely other software that is periodically checking for what hardware is connected and then interrogates the device. The Intel Matrix Storage Manager does this and I would expect that there are other software packages that may check to see if there is a disc in the optical drive. If no optical drive is connected then there is no interrogation process.

John

 

Well, according to windows it's a driver; it's called a driver, installed as a driver, and without it, or with it disabled, the CD/DVD drive does not work. That's a driver or a driver-component in my book. Ref. attached image. BTW, I can't find anything called "Intel Matrix Storage Manager" on my system,

Your last point makes sense. Anyway, the point is that with this software component enabled there is a terrible DPC latency, and by disabling it the latency is gone. To my knowledge there is no mysterious/dubious software running that should need to hog the driver callback system in the way shown by the DPC graph in my previous posting, but that doesn't rule out that there actually is some fishy stuff creating this side effect. I have no idea about what that might be though. I've tried to selectively disable most drivers and the anti-virus software etc., and only the mentioned component made any difference. FYI the machine is running the XP installation that it came with, minus a few services and possibly some bloatware I might have removed (hard to recall after more than three years).

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YES!! THANKS!!

running a Vostro 3700 and every 15 seconds I got a latency spike.
followed your advice, shut down, remove battery, and power up, and voila! no spikes!

UPDATE: you only have to rip out the battery and spikes disappear!


my 4 hour ordeal is over haha
and it doesn't matter that I have to run off mains because my external soundcard needs AC power because it can't run off laptop power anyway.
meaning I can use the normal inbuilt sound elsewhere because it doesn't require low latency.

thanks a lot!

now I wonder what dell will ever do about latency issues... cook some curry maybe?

 

DPC latency isn't consistently bad on the E6510. It was one of the first things I tested when I got the system and it seemed better then. I haven't installed any new drivers but obviously I've made configuration changes and installed new software.

One odd thing I've noticed is that DPC Latency Checker mostly reports green bars when it's the active application. When it's running in the background I get yellow and red spikes.

 

Uhh... you have a maximum of 188000us in your screenshot there; Windows design specs forbid anything larger than 100us.

LOL wow! Make a flash video or gif; I'd love to see that.

 

OK. That's a Microsoft standard driver which, in your case, is very ancient. Mine (for Windows 7) is dated June 2006.

I still think the culprit is something that periodically checks if a disc has been put in the drive. What about burning software, photo managers, etc.? Anything that springs into life when you do put a disc in the optical drive.

John

 

The driver I questioned is the latest version that I can find.

I agree that your theory is sound. However I can't find any running processes or services which are likely suspects. Of course, there may be some really sneaky stuff that is well hidden somehow.

I guess I'll just have to live with it. Luckily the driver can be disabled and enabled at run time, not requiring a reboot to take effect, so it can be managed that way. In any case I've just got a new Studio 17 which will be used for audio recording and processing, so it's not really critical anymore (here's hoping that I'll not run into any latency horrors there...).

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