Can a PowerMac 8600/200 run in 1280x1024?

richj · Tuesday at 7:30 PM

I just picked up a PowerMac 8600/200 with 256MB. https://lowendmac.com/1997/power-mac-8600/ says that the video supports 1280 x 1024 at 8 bits with 2 MB VRAM but I'm unable to get the Monitors control panel to show anything over 1152x870, even when 256 colors or grays is selected.
I'm using a Dell 1905FP monitor which supports 1280x1024.
I've tried two different DB15-to-VGA converters: One with no dip switches, which results in no video at all. The other with 6 dip switches with listings for 8 different modes on the back (21" multimode, 17" multimode, 13" multimode, VGA/SVGA, 21" 1152x870, 19" 1024x768, 16" 832x624, and 13" 640x480). I currently have the first mode selected.
Perhaps I need a different DB15 to VGA converter?

rieSha. · Tuesday at 8:50 PM

Yes. The 8600/200 can definitely do 1280x1024. This seems to be an adapter issue.

richj · Tuesday at 10:06 PM

rieSha. said:
Yes. The 8600/200 can definitely do 1280x1024. This seems to be an adapter issue.

OK, that's good news. Are you running with a DB15-to-VGA adapter? If so, which one?

Unknown_K · Tuesday at 10:40 PM

Could be refresh related, try a CRT monitor if you have one.

mikes-macs · Tuesday at 11:00 PM

I don’t know why your power mac 8600 doesn’t have a PCI video card. Mine came with one. With one of those you’d be all set. No need for adapters.

joevt · Tuesday at 11:27 PM

Try the 17" mode. If that doesn't work, try the VGA mode.

joevt · Tuesday at 11:40 PM

What version of Mac OS?

joevt · Tuesday at 11:42 PM

What modes do you see besides 1152x870?

richj · 2026-01-28T00:42:09+0000

Unknown_K said:
Could be refresh related, try a CRT monitor if you have one.

Unfortunately I don't have one.

richj · 2026-01-28T00:45:32+0000

mikes-macs said:
I don’t know why your power mac 8600 doesn’t have a PCI video card. Mine came with one. With one of those you’d be all set. No need for adapters.

There is also a video card with a VGA connector, but it appears to max out at 640x480.

richj · 2026-01-28T00:51:00+0000

joevt said:
What version of Mac OS?

I installed 7.5.5 on a SCSI2SD card, but get the same video resolutions as the SCSI disk it came with that runs Mac OS 9.1.

richj · 2026-01-28T00:52:50+0000

joevt said:
What modes do you see besides 1152x870?

I see 640x480, 832x624, 1024x768, and 1152x870.

rieSha. · 2026-01-28T21:07:23+0000

richj said:
OK, that's good news. Are you running with a DB15-to-VGA adapter? If so, which one?

A generic one with 10 DIP switches. I set it to 21" Multiscan.

Boctor · 2026-01-28T21:38:35+0000

To be sure, gave this a try on a ten-switch adapter with a PM7200's built in video, and was finally able to see the "missing" 1280x1024 mode as well. The 21" Multiscan (MODE 1 if applicable) works great for getting the desired behavior out of the sense lines.

joevt · 2026-01-28T23:26:59+0000

richj said:
I see 640x480, 832x624, 1024x768, and 1152x870.

Use the Control Strip instead of the Monitors control panel to see the 1280x960 and 1280x1024 options.

The Monitors control panel doesn't show those options because they are not marked as safe? The SwitchRes software may be able to fix that.

richj · 2026-01-28T23:27:17+0000

Mystery solved. The 1280x1024 resolution appears in the Monitors & Sound control panel, but not in the Monitors control panel, so I was looking in the wrong place. With the dip switches set to 21" multimode I can now see all of the following in Monitors & Sound: 640x480, 832x624, 1024x768, 1152x870, 1280x960, and 1280x1024. The two 1280 modes are missing from the Monitors control panel.

Can a PowerMac 8600/200 run in 1280x1024?

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