***M18x - NVIDIA SLI (Driver Questions, Performance, Problems) Discussion Thread***

[Mr. Fox]

Wow, that Clevo was way out of control. It's good you were able to finally tame it, but you were not kidding about the DPC latency being off the charts.

[lash444]

About the DPC issue. I had a problem with the Killer-N spiking my DPC latency, but I installed the latest drivers from Bigfoot, and removed the software from startup and services (I think). That part disappeared. My DPC latency goes yellow quite frequently, but the moment I actually run a game my latency is all green and very low. Those of you fighting your DPC latency, start up a windowed benchmark and watch it.

In an ideal world I don't want to see any yellow bars at any point, but if I am seeing all green the entire time the systems under load, then that is good enough for me.

[Mr. Fox]

About the DPC issue. I had a problem with the Killer-N spiking my DPC latency, but I installed the latest drivers from Bigfoot, and removed the software from startup and services (I think). That part disappeared. My DPC latency goes yellow quite frequently, but the moment I actually run a game my latency is all green and very low. Those of you fighting your DPC latency, start up a windowed benchmark and watch it.

In an ideal world I don't want to see any yellow bars at any point, but if I am seeing all green the entire time the systems under load, then that is good enough for me.

You're exactly right. Launched 3DMark11 in Window'd mode and DPC latency is very low when the GPUs are under load. Interesting.

[bumbo2]

Oh I have to check it when I get home!!!

[DR650SE]

Hmm, interesting. Didn't realize there were Latency issues, or at least I didn't pay attention. Driver related?

[Mr. Fox]

Yes, all NVIDIA drivers except for 269.03, A01 - the "official" Dell driver. (The beta posted by Dell has it bad and so do the reference drivers.) If you uninstall the NVIDIA drivers there is no latency. It's just really interesting that when the GPUs come under load the latency problem goes away. As soon as they enter power saving states it comes back.

I never tested this with 6990M CrossFire, so it would be interesting if an M18x owner with AMD could test it to see if the behavior is the same. If it is, then the latency may be masquerading as a video driver problem, when the problem is hiding elsewhere.

The good part is that the DPC latency has not been showing up in audio or video playback... at least not for me. It is "latent latency" with no adverse symptoms so far... knock wood.

[bumbo2]

Yes, all NVIDIA drivers except for 269.03, A01 - the "official" Dell driver. (The beta posted by Dell has it bad and so do the reference drivers.) If you uninstall the NVIDIA drivers there is no latency. It's just really interesting that when the GPUs come under load the latency problem goes away. As soon as they enter power saving states it comes back.

I never tested this with 6990M CrossFire, so it would be interesting if an M18x owner with AMD could test it to see if the behavior is the same. If it is, then the latency may be masquerading as a video driver problem, when the problem is hiding elsewhere.

The good part is that the DPC latency has not been showing up in audio or video playback... at least not for me. It is "latent latency" with no adverse symptoms so far... knock wood.

I did test this with 6990M crossfire, and the AMD don't have DPC latency.

[Mr. Fox]

Thanks, bumbo. Good to know. I can vaguely remember checking this out when skygunner found DPC latency issues with the first 580M setup he had and I did not remember DPC latency being a problem with the AMD-powered M18x. I may start a thread on this soon and ask for some screen shots from owners of M18x with AMD video cards.

[ejean]

Hi all,
There are 2 problems with my M18x.
1. Does anyone know what the cable is? I found it dangling in my refurbished M18x.

2. There are 2 Nvidia 580m in SLI mode in my M18x. After running some programs, the BIOS only detects one video card. Is there any tools or programs can detect the problems?

Thanks for any help!

Best regards,
Ejean

[Riftwire]

That cable looks like the one for the wireless HD card. They probably just took it out (or it never had it) and left the cable in there.

As for the video cards in windows does it detect two card or one? Also is SLI enabled in your driver options? The card could also not be 100% seated correctly but that would require you to take the computer apart.

EDIT: One more thing that might be causing a problem is the SLI cable that could also not be seated correctly.