3007WFP-HC, cannot change resolution from 1280x800?

@PWu  Just having a DVI-D cable doesn't mean you can run dual link DVI.  Every DVI connector on a graphics card always has the necessary holes for those pins in the cable, but that doesn't mean it actually supports dual link DVI.  And you didn't even specify what laptop you have or exactly how you're connecting this DVI cable to it.  I'm not aware of any laptops that have an Core 7th Gen CPU and a built-in DVI connector, so it seems you'd have an adapter or docking station involved somewhere.  And that adapter can be another source of inability to run dual link DVI.  If you're using something like a simple HDMI to DVI adapter, those will not run dual link DVI, even if the source HDMI port would support 2560x1600 when using native HDMI.

@PWu  As a general tip, when asking for technical assistance, it helps to provide full technical detail so that the people here who are willing to help have something to work with. You still haven’t specified what exact laptop you’re using — it’s not like there’s a ban on talking about non-Dell laptops here if that’s what you’re worried about — and now you mentioned a docking station without specifying the actual model. And then you said you have a “DV (DisplayPort)” output. Even if that “DV” was supposed to be “DVI”, DisplayPort and DVI are completely different outputs.  And if that DV was supposed to be DP (DisplayPort), then most DisplayPort to DVI cables/adapters only support single link DVI. There are some that support dual link DVI, but they’re quite a bit more rare and expensive.

Thanks for your quick response @jphughan .  I have a laptop which uses USB-C to the docking station.  Docking station has a DV (DisplayPort) output.  So, I connect the 30" monitor with a DV to DVI cable.  However, can't get anything better than 1280x800.  Any thoughts?  Thanks.  

PWu

@PWu  Ok, that's quite a bit more helpful, especially the reference to the additional display, because that adds another complication.  But here goes:

The max resolution spec on the DisplayPort output only applies if you're actually using native DisplayPort, i.e. connecting to a display that has a DisplayPort input.  Typical DisplayPort to DVI adapters rely on the source port supporting a capability called "Dual Mode DisplayPort".  This lets the DP output fall back to HDMI/DVI signaling.  The dock supports that, but again it would only support single-link DVI.  There are more complex DP to Dual Link DVI adapters that essentially keep the source port running in native DisplayPort mode because those adapters have a converter chip built into the adapters themselves, and those chips support dual link DVI output.  That's why it's possible to run 2560x1600 through those, but that's also why those adapters are quite a bit more expensive.  (Another reason is that dual link DVI is obsolete and was never very popular at all because at the time it existed, 2560x1600 displays were very expensive, and by the time their cost came down to a level that more of the market could afford, DisplayPort had arrived.)

So if you want to run 2560x1600 to your display, you're going to need a DisplayPort to Dual Link DVI adapter, not a simple DisplayPort to DVI cable.

But the additional complication is that secondary display.  The regular ThinkPad USB-C Dock you have can only access a certain amount of display bandwidth from the system, and I'm pretty sure you won't have enough to run 2560x1600 and another display at the same time, unless maybe that other display uses a very low resolution.  Unfortunately you didn't say any more about that other display.  But as indicated in this Lenovo table, if you want to run two displays from a ThinkPad USB-C Dock, the most you can do is dual 1920x1080.  With a single display you can run up to 4K 30 Hz, which means 2560x1600 60 Hz would also be possible, but again I don't think you'll have enough bandwidth for much else.  However, according to Lenovo's specs on the ThinkPad X1 Yoga Gen 2 here, it has a port that supports Thunderbolt 3.  That means that if you were to get a Lenovo Thunderbolt 3 Dock, like the current Thunderbolt 3 Dock Gen 2 (40AN), you'd be able to tap into 4x more video bandwidth than your current USB-C dock can access.  That means that the TB3 dock when paired with your system would be able to run dual 4K 60 Hz displays, or triple 2560x1440 displays.  The TB3 Dock Gen 2 doesn't have a VGA output, but you can get a DisplayPort to VGA adapter for that -- or better yet if your second display has some other input, you can stop using ancient VGA entirely and enjoy the superior image quality you'd get from any other input since everything else is digital, whereas VGA is analog and looks noticeably worse as a result.

See how much more information you can get when you provide more details about your setup?

Thanks @jphughan for helping. Sorry for the rookie wording.  I'm running a thinkpad yoga x1 (Lenovo MT 20JE_BU_Think_FM_ThinkPad X1 Yoga 2nd).  It has Intel (R) HD Grpahics 620. 

I'm running a Lenovo Thinkpad USB-C Dock model DK1633.  Type 40A9. The docking station has 2 DP (not DV which I goofed the last email up).  These two connectors are rectangular in shape with a corner cut off.  I checked my cable, which looks like this. I also run another monitor on VGA, which I unplugged for this test to go into single monitor mode.

I found the docking station info at

https://download.lenovo.com/pccbbs/options_iso/tp_usbc_dock_sp40l36280_ug_en.pdf  

I found info here on Max resolution and 

x

I tinkered around, but with no luck.  I still have only 1280x800 available to me. 

Let me know what you think, I really appreciate it. 

Peter