Wanting to fix USB bandwidth to get to 120hz mode! Could USB 3.0 be the solution?
I've recently bought the 3D Vision kit and everything seems to be working alright after knocking it down to 100hz due to mad flicker. After reading through this forum, I found that a PCI USB 2.0 card may not provide the amount of bandwidth needed to run at 120hz, hence the issue. My motherboard USB ports do not work at all, so plugging it into one of them isn't a solution.

I'm trying to find the solution and I may have one, just wondering if it worked for anyone else. What about a pci-e 1x USB 3.0 card? Obviously, since it can support up to USB 3.0 speeds, I figured the bandwidth should be fine. But has anyone tried this? I don't know if it detects a USB 2.0 device, goes to USB2 speeds and may cause other issues instead of maxing out USB2.

Specs in case they're important. Zotec 1gb GTX 560 ti, 8gb DDR2, AMD Athlon 2 4x 3.0Ghz all in an ASUS M2NPV-VM motherboard.
I've recently bought the 3D Vision kit and everything seems to be working alright after knocking it down to 100hz due to mad flicker. After reading through this forum, I found that a PCI USB 2.0 card may not provide the amount of bandwidth needed to run at 120hz, hence the issue. My motherboard USB ports do not work at all, so plugging it into one of them isn't a solution.



I'm trying to find the solution and I may have one, just wondering if it worked for anyone else. What about a pci-e 1x USB 3.0 card? Obviously, since it can support up to USB 3.0 speeds, I figured the bandwidth should be fine. But has anyone tried this? I don't know if it detects a USB 2.0 device, goes to USB2 speeds and may cause other issues instead of maxing out USB2.



Specs in case they're important. Zotec 1gb GTX 560 ti, 8gb DDR2, AMD Athlon 2 4x 3.0Ghz all in an ASUS M2NPV-VM motherboard.

#1
Posted 08/02/2011 11:54 AM   
I don't think your flicker problem is due to usb speed issues. However, USB speed/bandwidth issues have been reported to influence ghosting. Never experienced flicker myself, maybe someone else can shed a light on this.
I don't think your flicker problem is due to usb speed issues. However, USB speed/bandwidth issues have been reported to influence ghosting. Never experienced flicker myself, maybe someone else can shed a light on this.

#2
Posted 08/04/2011 12:15 AM   
[quote]My motherboard USB ports do not work at all, so plugging it into one of them isn't a solution.[/quote]
Waaaait a minute, why aren't your motherboard USB ports working???
My motherboard USB ports do not work at all, so plugging it into one of them isn't a solution.


Waaaait a minute, why aren't your motherboard USB ports working???

#3
Posted 08/04/2011 01:30 AM   
i use my 3dvision using the standard normal usb speed. All fine here
i use my 3dvision using the standard normal usb speed. All fine here

#4
Posted 08/06/2011 08:15 AM   
I very much doubt NVidia is pushing more than few hundred bytes a frame over USB and it could be < 1 byte a frame depending on how smart the emitter is.
USB bandwidth is all but irrelevant.
Latency on the other hand is critical, that's going to be a function of the emitter driver, the USB driver, along with unfortunately potentially every other kernel mode driver in the system, I doubt it being plugged into a PCI slot makes a substantial difference other than it using a different driver.

USB really was not the best way to connect an emitter, sending an additional signal over the video interface would have guaranteed the timing at least to sync the shutter signal and the frame, even then they'd have had to deal with the latency the monitor introduced.
I very much doubt NVidia is pushing more than few hundred bytes a frame over USB and it could be < 1 byte a frame depending on how smart the emitter is.

USB bandwidth is all but irrelevant.

Latency on the other hand is critical, that's going to be a function of the emitter driver, the USB driver, along with unfortunately potentially every other kernel mode driver in the system, I doubt it being plugged into a PCI slot makes a substantial difference other than it using a different driver.



USB really was not the best way to connect an emitter, sending an additional signal over the video interface would have guaranteed the timing at least to sync the shutter signal and the frame, even then they'd have had to deal with the latency the monitor introduced.
#5
Posted 08/06/2011 02:07 PM   
I'm not sure what else they could use. Sending it along with the video signal is fine but then how do you get the emitter to tap into that signal? Split the video cable?

The old RS232 and LPT ports would probably work fine, as would the old mouse ports. Unfortunately, those are vanishing off of machines and laptops certainly aren't going to have them. USB is pretty much the only game in town now. Use that or make your own card to plug in.
I'm not sure what else they could use. Sending it along with the video signal is fine but then how do you get the emitter to tap into that signal? Split the video cable?



The old RS232 and LPT ports would probably work fine, as would the old mouse ports. Unfortunately, those are vanishing off of machines and laptops certainly aren't going to have them. USB is pretty much the only game in town now. Use that or make your own card to plug in.

#6
Posted 08/06/2011 02:42 PM   
The best bet would have been to either add a connector on the video card, or have something in line with the Dual Link DVI connector. Either way they could have had it all in the same driver, and tied the signal to the frame output.

Windows isn't really the best OS Kernel to have real time requirements on driver latency, if all the drivers in a system are "well behaved" it's a not really an issue, but unfortunately your relying on a lot of manufacturers to provide well behaved drivers.
The best bet would have been to either add a connector on the video card, or have something in line with the Dual Link DVI connector. Either way they could have had it all in the same driver, and tied the signal to the frame output.



Windows isn't really the best OS Kernel to have real time requirements on driver latency, if all the drivers in a system are "well behaved" it's a not really an issue, but unfortunately your relying on a lot of manufacturers to provide well behaved drivers.
#7
Posted 08/06/2011 11:15 PM   
Thought I'd bump this to say I bought a USB 3.0 PCI-E 1x card as I was buying a USB 3 hard drive anyway and it has fixed it. Getting 120Hz and barely any ghosting now.
Thought I'd bump this to say I bought a USB 3.0 PCI-E 1x card as I was buying a USB 3 hard drive anyway and it has fixed it. Getting 120Hz and barely any ghosting now.

#8
Posted 11/02/2011 08:54 PM   
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