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Drivers & Software

Journeyman III

Will AMD ever fix custom resolution pixel clock limitations?

I'm just going to paste what i wrote into the Driver Issue Reporting form. If someone could help me with this, then I would be really happy. I'm sorry for any typing errors you might find.



I have been trying for multiple weeks, even months to get some custom resolutions to work on my PC. This message is going to be rather short compared to what it could have been if i went into full detail about every sort of an issue I've had, but it's going to be concise to try to comprehensively explain my current issues in a way that you can reproduce them.

I am experiencing a lot of issues when trying to add custom resolutions on my water-cooled dual R9 280X crossfire setup. My display device is an Eizo F931 CRT monitor from 2001. I know it's an old monitor, but I really, really hope my message isn't going to be disregarded because of this. Many people still use CRT monitors, because they inherently have some characteristics that LCD monitors don't have. I'm not going to write more about that here, but if you are interested in knowing why, there is a wiki on Reddit named "GloriusCRTMasterRace" explaining why some people still in 2017 prefer CRTs over LCDs. I'm not going to post links here as I'm afraid my whole problem reporting form is going to be disregarded or ignored because some sort of a spam filter could be kicking in.

Part of my issue is covered on the forum My username over there is "sevs".

OS is Windows 7 x64.

My problems are mainly these three:

1. The custom resolutions tool provided in your latest Crimson drivers under the Display tab have an artificial pixel clock limit of around 330MHz for some reason.

Circa Version 16.2.1 and before had the custom resolution menu under the Radeon Additional Settings window. This version and before had a pixel clock limit of around 650-680MHz, when using progressive resolutions, which is a nice and high number. It always had a pixel clock limit of 330MHz when using interlaced resolutions though, which on the other hand was/is a huge problem. This was tested using ToastyX' Pixel Clock Patcher.

Back when I had a dual ATI HD5770 setup, i could add custom resolutions without problems using ToastyX' Custom Resolution Utility. I was limited to a pixel clock of 400MHz though, which was one of the reasons why I upgraded to my current setup.

2. Sometimes my monitor flickers on and off and my computer becomes totally unusable until i reboot (or press F8 (recovery mode) in the restart.exe in the ToastyX' Custom Resolution Utility folder/zip). This is probably because my monitor is connected using BNC cables, thus not supplying any EDID data to the GPU. I can see the Windows Screen Resolution window looping between “Display device on: VGA” and “Generic Non-PnP Monitor”, with a minimal but annoying flicker between each switch. Sometimes the monitor(s) loop between two different resolutions which means they switch off briefly between a resolution change, so you can only see what’s on screen for a split second every time it flickers.

i have really lost grasp on what exactly starts "enabling" this problem, but when it is "enabled" (I am at a lack of words, sorry), the problem is triggered either by clicking the "Display" tab in the latest AMD Crimson drivers (at least version 17 and above), or some other times it starts happening by itself after using the computer for 5-10 minutes.

3. Sometimes the custom resolution is being sent from the card, but it doesn't show up in the Windows Screen Resolution window or the List All Modes window. instead, some other resolution is being upscaled (like for example 1600*1200) using some sort of a GPU scaling. The Windows Screen Resolution window or the List All Modes window. reports for instance a 60Hz progressive resolution and refresh rate, but in fact the monitor, and the real resolution could be something like 1920*1440 at 160Hz interlaced. I can clearly see when this happens as everything looks unsharp and upscaled, whereas whenever a non-scaled resolution is sent to my CRT monitor, everything is a lot sharper, especially text. One can confirm the scaling that is going on by going to (a monitor test pattern page) and clicking LCD calibration, then going to the Clock and phase tab at the top. The test pattern should be evenly gray from a distance and not have a sort of wave pattern. If you move the browser window around when this issue is present, the artifacts become obvious.

This issue can't be turned off just by disabling "GPU Scaling" in the Crimson drivers, in fact GPU scaling is already turned off when this happens as this issue seems to be independent from this functionality.

((on a side note, i would love to see some features added to the GPU scaling functionality, like the ability to choose a different display aspect ratio than the game/software/windows aspect ratio but disregard this for now as it's irrelevant to my issue))

Steps to reproduce all problems:

1a. You need a CRT PC monitor with a horizontal scanrate of at least 130KHz (and a vertical scanrate of at least 160Hz). I know for a fact AMD is an US based company, and I don't think it should be hard to find a CRT monitor of this sort of a spec in California or around. I'm from Norway and I had to travel across the country to find mine lol. You should check your local Craigslist or similar if you don't have any CRTs at your headquarters, and find the model number and google it. CNET is a good site to check specifications for CRT monitors. They almost always supply a horizontal scanrate, and it is almost always correctly specified.

Keep in mind that CRT TVs are way different than CRT PC monitors and thus are not applicable.

This monitor needs a (5x) BNC input.

1b. You also need a (preferably good quality) BNC to DVI-I cable. I could supply a link for a fairly good and cheap one, if you reply to the email address supplied further down in the survey form. If you can't pick up a DVI to BNC cable, you could always use a BNC to VGA cable and put a DVI-I to VGA (DB15) adapter on the end, but the image quality wouldn't necessarily be the best. The signal that is transmitted on this type of cable is called RGBHV, and is analog.

1c. You need a fairly late AMD graphics card that has an analog (DVI-I) output and an internal RAMDAC. Preferably a Tahiti GPU like the 280X that I have, to fully reproduce my issues.

2. Install Windows 7 x64 on a cumputer with said graphics card installed. Install any AMD driver you'd like, but start with the latest one (version 17.9.1 as of today 9th of september 2017), to not get disrupted by other issues that my occur because of other issues with older drivers). Download and run ToastyX' Pixel Clock Patcher and ToastyX' Custom Resolution Utility.

3. Use whatever software, drivers and others that you want to try to add and use the following custom resolution, (but stay on Windows 7 x64):

1920*1440 at 160Hz interlaced (80Hz fieldrate, 160Hz refresh rate)

Hopefully if you take these three steps to reproduce my problem(s), you will have issues underway, and you will be able to find what causes the problems and fix them.

I'm sorry this became a long message, but I really, really hope someone reads though this whole mail thing and takes it into consideration. My pizza got cold after typing all of this lmao

Feel free to contact me on the supplied email address if anything is unclear or if you have any questions.

Thank You for reading and Best regards.

2 Replies
Journeyman III

Re: Will AMD ever fix custom resolution pixel clock limitations?

same here 😕

Journeyman III

Re: Will AMD ever fix custom resolution pixel clock limitations?

these issues still persist

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