Looks like 960 x 600 and 640 x 400 - simply multiply all pixels 3x and 2x.

Reminds me of an old thread from about 20 years ago.
True aspect ratio of VGA mode 13h (320x200)?

Some 320x200 game graphics were made with paint programs that weren't aware of non-square pixels in mode 13h.
Thus, the drawing function for circles wasn't being compensated for.
Which make them look correct on modern LCD now but didn't on period-correct CRTs of their time.

Grzyb wrote on 2025-08-09, 11:39:

Looks like 960 x 600 and 640 x 400 - simply multiply all pixels 3x and 2x.

Does this mean this computer can draw DOS games properly?

AlessandroB wrote on 2025-08-09, 15:14:

Does this mean this computer can draw DOS games properly?

No.
960 / 600 = 640 / 400 = 1.6
Proper ratio is 1.333

Grzyb wrote on 2025-08-09, 15:31:

No. 960 / 600 = 640 / 400 = 1.6 Proper ratio is 1.333 […]
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AlessandroB wrote on 2025-08-09, 15:14:

Does this mean this computer can draw DOS games properly?

No.
960 / 600 = 640 / 400 = 1.6
Proper ratio is 1.333

but
320x3=960
200x3=600

CRT monitors have 4/3 = 1.333 width/height ratio.

The following modes provide square pixels:
320 x 240
400 x 300
512 x 384
640 x 480
800 x 600
1024 x 768
(...)

In 320 x 200 modes, pixels are NOT square on CRT monitors.

On LCD displays, physical pixels are square - and so are the 3x3 physical pixel groups that represent a single pixel of the 320x200 mode.

Grzyb wrote on 2025-08-09, 17:20:

CRT monitors have 4/3 = 1.333 width/height ratio. […]
Show full quote

CRT monitors have 4/3 = 1.333 width/height ratio.

The following modes provide square pixels:
320 x 240
400 x 300
512 x 384
640 x 480
800 x 600
1024 x 768
(...)

In 320 x 200 modes, pixels are NOT square on CRT monitors.

On LCD displays, physical pixels are square - and so are the 3x3 physical pixel groups that represent a single pixel of the 320x200 mode.

ok, but on my crt i clearly see that the pixel are square, or is an optical effect??? And i see in this thinkpad that the pixel is square and the proportion are not clearly deformed… or is my mind that fix the issue???

AlessandroB wrote on 2025-08-09, 18:19:

ok, but on my crt i clearly see that the pixel are square, or is an optical effect??? And i see in this thinkpad that the pixel is square and the proportion are not clearly deformed… or is my mind that fix the issue???

The deformation isn't that big to be obviously visible.
Also, on CRT monitors, picture ratio is subject to adjustments.
You may need to precisely measure it to know that pixels aren't square.

I've just set the 320 x 200 mode on my CRT monitor, adjusted H-SIZE and V-SIZE so it fills the entire screen - but without distorsions in the corners! - and did the measurments:
276 x 205 mm
So the ratio is 1.346 - very close to the theoretical 1.333, and far from the 320/200 = 1.600.

Grzyb wrote on 2025-08-09, 19:08:

The deformation isn't that big to be obviously visible. Also, on CRT monitors, picture ratio is subject to adjustments. You may […]
Show full quote

AlessandroB wrote on 2025-08-09, 18:19:

ok, but on my crt i clearly see that the pixel are square, or is an optical effect??? And i see in this thinkpad that the pixel is square and the proportion are not clearly deformed… or is my mind that fix the issue???

The deformation isn't that big to be obviously visible.
Also, on CRT monitors, picture ratio is subject to adjustments.
You may need to precisely measure it to know that pixels aren't square.

I've just set the 320 x 200 mode on my CRT monitor, adjusted H-SIZE and V-SIZE so it fills the entire screen - but without distorsions in the corners! - and did the measurments:
276 x 205 mm
So the ratio is 1.346 - very close to the theoretical 1.333, and far from the 320/200 = 1.600.

I used your empirical method and measured 268mm x 167mm and the result is a ratio of 1.6. In reality it should have been 268mm x 200mm and the difference is significant, yet to my eye the games look quite correct, just as I remembered them.

I probably shouldn't ask this, but.. why?
These kinds of games (pixel art, point&click) unfold their beauty on a CRT.
So what difference does correct/incorrect aspect ratio make on an LCD?

Jo22 wrote on 2025-08-10, 18:10:

I probably shouldn't ask this, but.. why?
These kinds of games (pixel art, point&click) unfold their beauty on a CRT.
So what difference does correct/incorrect aspect ratio make on an LCD?

For various reasons. As a computer enthusiast from the golden age, I also really like notebooks, especially those from the 90s, where the compromises revealed great capacity for innovation and courage on the part of designers and brands. I like the idea of ​​having a retro notebook (actually, I have more than one, including the beautiful PowerBook 12, the rare Canon with integrated inkjet). Having chosen to collect the IBM brand for its long history, I chose this laptop model that combines excellent design and construction with a certain compatibility with the DOS world. I agree that the colors of CRTs are significantly better, but I've never liked the blurry effects of CRTs. I've always loved the precision of LCDs where at 1024x768 you could count the pixels that made up the image one by one. For this reason, the CRT I chose is a Trinitron, because in my opinion it is the one that comes closest to the precision of LCDs in rendering individual pixels.