256x256 resolutions on horizontal monitor

[Pingaloka]

Hello people, I have a TV CRT, with a RGB to Scart cable, and I operate with Winmodelines.
I have the TV installed horizontally in my cab. Most of the horizontal games work fine.
But there a few that I cannot get a propper image. Games like zookepper, with a 256x256 res, doesn't work well
in my monitor as I get an "interlaced" image. Same happens with games like stargate or blaster with a res of
292x240. What's the reason for this? Do these game runned in different types of monitor, not sending
15Hz? Sorry for my complete ignorance in this matter.

[Gray_Area]

Zoo Keeper is 256x240. If your modelines are correct, your video card/video drivers may be the culprit.