Recommend a good laptop without the NVIDIA Optimus?

1
Hello,

We are using a Lenovo Thinkpad W520 laptop for an experiment with high demand on timing. A web camera captures images in real time that are processed by the laptop before displayed to the subjects. The display is as fast as 30 frame per second under the single display mode. However, we need the processed images to be displayed not only on the laptop monitor but also on an extra display device. We found both the dual display mode and the clone mode provided bad timing as slow as 7 to 10 fps. And the operating system is Windows 7.

Both the operating system and the NVIDIA Optimus may kill the timing. Now we are considering to buy a new laptop with only one high-end graphic card. Does anyone have any idea what brand and model we should try? I just chat with a Dell representative. Unfortunately, she said all their recent products supported NVIDIA Optimus. I know this is an advanced technology. But it may be not good for Psychtoolbox for now.

Thanks for any suggestion!
2
Hi Mario,

Thanks for your suggestion! We are trying to install WinXP on the laptop though have some troubles on the installation. So we will let you know its performance with optimus disabled in the BIOS later. We use Image Acquisition Toolbox of Matlab to capture video images, but we are interested in PsychVideoCapture. It seems it's still a beta version? How long do you think you will support it? How fast can it control a camera to capture images?

Thanks!



--- In psychtoolbox@yahoogroups.com, "Mario" <mario.kleiner@...> wrote:
>
>
>
> You are lucky in your hardware choice, at least if we believe the internet.
>
> A good Optimus Laptop would be what you already have: The Lenovo Thinkpad W520. If we believe the wisdom of the internet, then your laptop has a rather sane design for Optimus:
>
> <http://zachstechnotes.blogspot.com/2012/01/tri-head-display-on-linux-thinkpad-w520.html>
>
> <https://bbs.archlinux.org/viewtopic.php?id=132974>
>
> also
>
> <http://forum.notebookreview.com/linux-compatibility-software/473915-no-support-nvidia-optimus-linux-8.html>
>
> So, according to these posts (start with the first one) you can select in the BIOS setup of your laptop if it should use Optimus, or if it should use non-Optimus-mode and stick to either the Intel card or the NVidia card. The Laptop has hardware multiplexers, so if you disable Optimus it should work without any of the shady driver tricks and give decent performance and work correctly with Psychtoolbox and similar toolkits -- proper visual stimulus onset timing and timestamping.
>
> Try if switching to the discrete nvidia card only helps your problems. Any further problems would then be related to Windows-7, the worst possible operating system for visual stimulus presentation, especially for multi-display operation. According to the posts above, Linux should work fine in "discrete nvidia" card mode, so that is always an option.
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> One tricky timing problem if you use a clone or dual display mode is that one of the two monitors in the clone configuration must drive the timing of display flip. As the monitors are unsynchronized, you must make sure that the external stimulus monitor is the "primary" monitor that drives the flip timing/timestamping, otherwise weird things may happen wrt. timing and timestamps or tearing artifacts or lowered framerate. PTB also provides its own mirroring implementation (help PsychImaging) which can help if the operating systems "clone" mode makes trouble.
>
> A "best case" for clone/mirror output would be if you run PerceptualVBLSyncTest and the external stimulus display shows nice tearfree flicker, whereas the internal Laptop panel shows severe tearing artifacts. That's what you want, because you usually can't get tearfree display and precise timing and good performance on a Laptop with internal + external display, due to the lack of synchronization of both displays. Therefore you need to make a choice which is the "good display" and verify timing etc. works for the good display.
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> If both displays show tearfree flicker for PerceptualVBLSyncTest that means trouble - generally reduced framerate, all kind of tremor patterns or jitter in presentation timing and a chance that your timing/timestamps relate to the wrong display. You could only reliably find out via photo-diodes and other external measurement equipment if everything is fine.
>
> Anyway, try these options first and report back how it works out. And probably consider use of Linux - Windows-7 and Vista are really unbeatably bad when it comes to good timing in multi-display mode.
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> Do you use ptb's built-in video capture engine and image processing? Or some other solution? Ptb's built in functions should provide quite a performance advantage for such realtime manipulated video feedback tasks.
>
> best,
> -mario
>
>
>
> --- In psychtoolbox@yahoogroups.com, "gogglesumn" <gogglesumn@> wrote:
> >
> > Hello,
> >
> > We are using a Lenovo Thinkpad W520 laptop for an experiment with high demand on timing. A web camera captures images in real time that are processed by the laptop before displayed to the subjects. The display is as fast as 30 frame per second under the single display mode. However, we need the processed images to be displayed not only on the laptop monitor but also on an extra display device. We found both the dual display mode and the clone mode provided bad timing as slow as 7 to 10 fps. And the operating system is Windows 7.
> >
> > Both the operating system and the NVIDIA Optimus may kill the timing. Now we are considering to buy a new laptop with only one high-end graphic card. Does anyone have any idea what brand and model we should try? I just chat with a Dell representative. Unfortunately, she said all their recent products supported NVIDIA Optimus. I know this is an advanced technology. But it may be not good for Psychtoolbox for now.
> >
> > Thanks for any suggestion!
> >
>