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Controlling DP and HDMI port settings on Precision 7720?
I have a 7720 coming next week with a Quadro P5000 Video card. I’m wondering if there’s anything special you need to do to ensure I’m getting P5000 capabilities on the miniDisplayPort and HDMI ports, rather than the integrated Intel graphics? Thanks, Wayne
jphughan
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October 22nd, 2017 19:00
Here's a bit more information/clarity:
- Built-in display panel: Always controlled by the integrated GPU, and this cannot be changed. The discrete GPU can still accelerate graphics on this panel by operating as a render-only device, but it cannot directly control the panel.
- VGA output wired to underside dock connector: Same as above.
- DisplayPort and DVI outputs wired to underside dock connector: By default, both controlled by the discrete GPU, but the "Enable Dock Display Port" BIOS setting allows DVI/DP #1 to be directly controlled by the integrated GPU. This can be handy if you're using the built-in panel and a single external display together. DVI/DP #2 are always controlled by the discrete GPU.
- All built-in display outputs, including Thunderbolt 3 / USB-C: By default, controlled by integrated GPU, but the "Special Graphics Mode" allows the discrete GPU to control them instead.
NOTE: It seems that if you disable "Switchable Graphics" completely, you may be able to get the internal panel and VGA outputs to be driven by the discrete GPU, but forum posts indicate that at least on the 7510, this means that you cannot undock while the system is asleep and have the built-in display start working. Instead, you have to shut the system down before undocking.
jphughan
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October 23rd, 2017 09:00
You wouldn't need to do anything special for highest possible frame rates except maybe configuring the drivers to force the game application to use the discrete GPU if that doesn't happen automatically (although it usually does), but if you want VR and 90 Hz, you'd definitely need to enable "Graphics Special Mode" so the discrete GPU directly controls the outputs since the integrated GPU does not support that.
jphughan
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October 22nd, 2017 18:00
I'm not sure this still exists for the 7720, but the 7710 (and 7510) had an optional "Graphics special mode" in the BIOS that forced the discrete GPU to control of all external display outputs. By default, the integrated GPU is used for those outputs (except the underside dock connector) and the discrete GPU is only enabled when Windows/drivers detect that its additional horsepower is required -- but even then, operates as a render-only device that passes completed frames to the integrated GPU for output rather than controlling the outputs directly.
Typically the only time you would need the discrete GPU controlling outputs directly would be if you're trying to use a display setup that isn't supported by the integrated GPU, such as a 5K display that doesn't support DisplayPort 1.4 and therefore requires TWO DisplayPort connections. To use such a display with your system, you would either connect a DisplayPort MST hub to your single DP output and then two of the outputs to the same 5K display, or use a TB16 dock. Either way, the Intel GPU would not support this configuration, but the discrete GPU drivers would, which is why Graphics you'd have to enable "Graphics special mode". Another case would be if you needed to use something like G-Sync.
But unless you plan to do something like that, even if you find that setting on your 7720, I would start by keeping it disabled. Running your discrete GPU that often will probably reduce your battery life significantly, and even if you find that the discrete GPU isn't running when you feel it should be (the difference will be obvious), you can usually tweak the drivers to make sure that the discrete GPU runs whenever a particular application is running. Start with the default settings and tweak as needed. :)
Hobneb
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October 23rd, 2017 08:00
Thanks! One thing, I want to be able to drive VR headset at 90hz and also get highest possible frame rates for games.
Hobneb
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October 24th, 2017 12:00
Thanks! I sure hope it works as Dell advertises the 7720 as VR Ready if you hav the P5000 (or 4000) graphics. I just got notified that my computer shipped today and will arrive tomorrow! Will let you know how it goes.
Hobneb
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October 26th, 2017 17:00
Good news and bad news. I got my 7720 yesterday and before it went belly up I checked the BIOS and there is a setting that assigns the discrete video card to all external ports. Couldn’t actually check it out as the machine stopped booting and couldn’t be resurrected after several hours on Tech Support. Replacement machine ordered, hopefully it will be a bit more reliable