The Mother Board

[sirams]

Last two days I've been trying to stop my HD 3650 video adapter from scaling the image.

I have a problem with a vision defect since birth so I cannot use the monitor at its native resolution, but as long as monitor has good scaling (interpolation) quality, I have no problems to set it to a smaller resolution.

I have this monitor:
http://www.asus.com/Display/LCD_Monitors/PA238Q/

and this motherboard:
http://www.gigabyte.com/products/product-page.aspx?pid=3779#ov
with Intel Core i3 CPU.

At first I was using Intel i3 built-in graphics. I found out that the best vertical pixel count for my eyes is 768, so the closest resolution for this was 1366x768. Intel built-in graphics worked just fine on any resolution I chose and on every connection (VGA, DVI).

Then I decided to try how ATI video cards will play with my new monitor. So I inserted my old HD 3650

http://www.asus.com/Graphics_Cards/AMD_Series/EAH3650_SILENTHTDI512M/

in PCI-E slot and booted. At the very first boot I noticed that my monitor shows a scaled image with black bars around. I hoped that the latest Catalyst drivers will solve the issue, so I installed them. And no luck. On VGA my monitor works fine, again I can set the 1366x768 resolution without any problems. But when I switch my monitor to DVI, I see those black bars around.

When I go to the settings page in Catalyst for "Digital Panel" (as AMD calls it), I see that "Enable GPU scaling" checkbox is enabled. Obviously, I do not want the GPU to scale the image (I've tried it, it's too blurry). So I want to set the monitor to 1366x768 and let the monitor deal with the scaling, it handles scaling pretty good (as I tested with Intel i3 GPU).

Then I uncheck the "Enable GPU scaling" checkbox and click Apply. But the checkbox immediately gets stubbornly checked again! I tried to use "Set centered timings" with a hope that then GPU scaling will go away, but then I see that my monitor reports that it is set to 1440x900 (why, AMD, where did you get this resolution from, it's not the one I have defined, nor it's the native resolution of my monitor)! And of course, black bars again.

And no matter how I try, I cannot set it to 1366x768 without GPU scaling. But the weird thing - if I set it to 1280x720, then suddenly the black bars disappear, GPU scaling options get grayed out, and my monitor reports 1280x720 and does a nice scaling. And on the VGA cable, it always works fine, no black bars, resolution is 1366x768 and also the monitor reports the same resolution.

Why am I not able to stop GPU scaling on AMD HD3650 for all resolutions and let my monitor do the job, as it is with i3 GPU? Is this a "feature" for all AMD/ATI adapters or just 3600 series?

If any of you have an AMD/ATI video card, please, could you try to set a resolution to 1366x768 on DVI monitor and report, if you have black bars or not and if GPU scaling can be disabled.

I just don't know what to buy next - new AMD video card? nVidia video? Maybe all of them have this problem? But then how Intel i3 works without problems?

Thanks for any ideas.

[Ripshod]

I'm running a HD5770 into a Iiyama 23" 1920*1080 via DVI and HDMI (switchable).
At default settings with 1366*768 resolution the monitor shows bars top and bottom on both DVI and HDMI.
If I go into the AMD VISION Engine control Center, into 'My Digital Flat Panels', I can enable GPU Scaling and select 'Scale image to full panel size', the image fits to the edges and is as clear as I would expect at that resolution.
I'm using Win7 x64, and driver version 12.4
Hope this helps!!

*edit*

I'm suresome graphics cards should be able to do the upscaling of a 1366*768 image themselves. If not, why not? The image would be a lot better (sharper edges).
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[sirams]

Thank you, so it seems even on HD57xx series AMD is using those black bars when GPU scaling is not enabled. That's not good.

I once again compared the quality of GPU scaling (from 1366x768 to 1920x1080) with the native monitor scaling (which for ATI card works only on VGA), well - the GPU scaling makes text more blurry. It seems, I'll have to live with VGA or return to the Intel built-in graphics.

What's weird - 1280x720 and 1024x768 work fine, no GPU scaling enforced, no black borders. Maybe there are only some resolutions, which the video adapter is unable to output as native, so it starts scaling?

I'm still curious, how the things are on nVidia video adapters? Does nVidia too enforce "GPU scaling" on some resolutions?

[Karlsweldt]

If interested, here is some tech info regarding video modes..

Resolution Standards For Graphics Displays:
Type.........Linear Pixels (HxW)....TotalPixels...........Aspect Ratio
CGA............320x200.....................64,200...................1.60
EGA.............640x350...................224,000...................1.83
VGA.............640x480...................307,200...................1.33
WVGA..........854x480....................410,240..................1.78
SVGA...........800x600....................480,000..................1.33
XGA...........1024x768....................786,432..................1.33
XGA+.........1152x864....................995,328..................1.33
WXGA........1280x800.................1,024,000..................1.60
WXGA+......1440x900.................1,296,000..................1.60
SXGA........1280x1024................1,310,720..................1.25
SXGA+.....1400xx1050...............1,470,000..................1.33
WSXGA.....1600x1024................1,638,400..................1.56
WSXGA+...1680x1050................1,764,000..................1.60
UXGA........1600x1200................1,920,000..................1.33
HDTV........1920x1080................ 2,073,600..................1.78
WUXGA.....1920x1200................ 2,304,000..................1.60
QXGA........2048x1536................3,145,728..................1.33
QSXGA......2560x2048................5,242,880..................1.25
QUXGA-W..3824x2400................9,216,000..................1.60

Refresh Rate Frequencies: (nominal)
Resolution.....Horizontal......Vertical
640x480........31.5 Khz..........60 Hz
800x600........48 Khz............72 Khz
1024x768......58 Khz............60 Khz
1280x1024 ....64 Khz............60 Khz
1280x1024 ....80 Khz............75 Khz


Aspect Ratios are defined by height x width
Aspect Fields: 1.25=5:4 1.33=4:3 1.56=25:16 1.60=16:10 1.78=16:9 1.83=11:6

A pixel, or dot-pitch, is defined as the triad of color phosphors that comprise the R+G+B colors, measured in mm from one same color to the adjoining same color. The closer, the sharper the image. Dot-pitch of less than .28 mm is considered very sharp.
Interlaced images refer to the odd-trace lines being scanned and then the even-trace lines being scanned consecutively.
Progressive images refer to the odd and even trace lines being scanned simultaneously per image.

If you cannot get the desired resolution to 'lock in', then try a different aspect ratio range.. or different refresh frequency.
Windows has a bad habit of 'enhancing' every feature, as it wants.. whether or not that is successful. Once a video mode is set with the 'apply' and then 'OK', it should be default. But some programs may change the default resolution to their own desires, and the only way to revert is to reboot. Most times, though, do a right-click on the screen and choose 'refresh'.
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F@H.. to solve mankind's maladies.. in our lifetimes!

[sirams]

Thanks for the resolution table. It made my suspicions even stronger. It seems, if I choose a resolution which is not in this standard list, the GPU processing is enforced for my HD3650 and I get black bars, if I do not set scaling mode to full. But why I get black bars only on DVI and never on VGA, that's another mystery.

[Karlsweldt]

A lot of movie (DVD) player programs will set video to a default 'letterbox' theme, whether or not the monitor is that type. For 'squarish' monitors, you may have black bars top and bottom. And for some wide-screen monitors, the program may set the video so you have black "curtains" at each side! The program should have a user-option feature to match video to the monitor.
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F@H.. to solve mankind's maladies.. in our lifetimes!