DisplayPort and Windows text rendering

[papadadfather]

When I plug my monitor (DELL U2311H) to my PC with a DVI cable, the text is perfectly clear and crisp. When I use a DisplayPort cable (I need the DVI port for another device now and the display only has one DVI port), the text is blurry and pixelated.

I have ran through the Windows ClearText thing multiple times and the text stays blurry. With DVI it was crisp right off the bat. What is causing this?

The signal should be the same: 1920x1080@60Hz.

 

[KingFatty]

Have you verified the monitor resolution when using the displayport (DP)?

Maybe the video settings are changing to a non-native resolution when connected by DP, perhaps you could verify by right clicking on the desktop and going to screen resolution, make sure it's 1920x1080 and not some smaller value (while the DP cable is being used)?

 

[papadadfather]

it's 1080p.

I think it has something to do with the color settings. ClearType smoothens the letters with different colored pixels around the letters (or so it seems, don't really know the specifics other than reading the Wikipedia article and staring at them really close). With DP these different colored pixels stick out more, creating a blurry, messy look.

By adjusting the color settings on the display towards a little more washed-out look and messing around with the ClearText test a few more times the text is starting to be clearer. But it's still not as crisp as DVI was right out of the box.

 

[notty22]

Try to boot to a linux release like Ubuntu, to rule out windows/software playing with display. It could be a setting or a cable etc. You don't want to settle if you can notice a difference.

 

[papadadfather]

Try to boot to a linux release like Ubuntu, to rule out windows/software playing with display. It could be a setting or a cable etc. You don't want to settle if you can notice a difference.

what's the easiest/least hassle distro to do this with? I have no experience with Linux.

 

[notty22]

Ubuntu 32 bit will boot from DvD drive. Just check trial, and installs nothing you get to a desktop with basic settings and usually full network/internet working.

 

[Tweak155]

Are you using a DVI -> DP adapter?

 

[papadadfather]

No. Just a normal DP-DP cable plugged from my GPU (6870) to the display.

I should note I guess it is the cheapest possible DP cable I could find from a Chinese Ebay seller because I figured it's a digital cable so they're all created equal. I know there are different versions of DP with different bandwidths etc. but I guess that is related to ports and not the cables themselves? And in any case you'd expect it to be able to output a normal 1080p. The cable came with no packaging so I have no other specific info.

 

[papadadfather]

Well I'm posting this from my usb ubuntu thing and yeah the text is crisper. So what's messing it up on Windows side?

 

[notty22]

Your video card drivers must be pushing a wrong frequency/timings to the monitor.
what card are you using. Do you have a monitor driver installed in the windows monitor panel? It's a simple step, that many don't bother with,because it changes little.

 

[papadadfather]

I did that and now it recognises my monitor's exact model. Didn't really see a visible change, what was supposed to happen?

Also about the font rendering on Ubuntu, I'm not sure it was communicating any different with my display, it's just a different font renderer altogether. I installed another font renderer (gdipp) and with it the text looked just about the same as on Ubuntu, crisper (and altogether so different I don't want to go through getting used to it) but I would say still not as nice and crisp as with DVI and Cleartype. But at this point I have been staring at the fonts for so many hours fiddling with little things I don't even know what is what anymore.

All I know is the picture is just a tad bit more messy for a lack of better word on DP compared to DVI. Maybe it's just a function of the technology.

 

[Throckmorton]

Because you're using a convertor to convert the signal from DP to DVI, and your convertor probably sucks.

Edit: Oh I see that monitor has DP input, so nevermind

 

[Telvin]

I should note I guess it is the cheapest possible DP cable I could find from a Chinese Ebay seller because I figured it's a digital cable so they're all created equal.

They're actually not. It's not so much a standards or version issue, but cheap cabling can seriously degrade and interfere with the connection quality. Now, anything you get from a site like newegg is probably good to go, but if you found a genuine $5 Chinese knockoff somewhere it really could be the source of your troubles.

And while it's not so much a problem with Display Port, HDMI version numbers can actually make a difference with the cables. Not in all cases, but it can screw you over when you least expect it.

 

[Wall Street]

My guess would be the graphics drivers. When I used the HDMI port on my GPU the drivers assumed I wanted overscan which ruins the pixel perfect 1:1 mapping of 1080p images on a 1080p monitor.

 

[Telvin]

Hey, yeah, overscan! It's usually more of a HDMI thing, but double check in the monitor's settings (on the actual monitor, not the computer's settings for the monitor) that it is set for 1-to-1 mapping for all the inputs.

 

[papadadfather]

Over/underscan slider in the scaling options is grayed out in CCC. Only when I'm using DP though, they're adjustable when I use the DVI port.

Telvin I'm not sure what you mean with the "actual monitor settings". Everything everywhere says it's both receiving and outputting 1080p. There are no scaling/1-1 pixel mapping etc settings in the side panel options.