maxtherabbit
Veteran Member
Ah, an everex viewpoint. Yeah I'd start by swapping the 2 socketed 4x256 chips
Sorry, I meant "replacing" them not just reversing their position which you said you tried alreadyYeah I tried swapping the two socketted ram chips first.
Just tried all 4 combinations of jumper settings, no effect.
I guess I can try that next, I spent some time yesterday desoldering and socketting the two ram chips in my OAK card so I can try popping those in. If that doesn't change anything I guess the next thing would be to desolder and socket the other two chips in the et4000Sorry, I meant "replacing" them not just reversing their position which you said you tried already
I suspect you are seeing DAC snow. Some early VGA cards had snow if the palette was changed without waiting for vertical retrace. I don't think there is any hardware fix.
What about 16 bit bus access? Could my xt-ide bios be hurting performance?
I still suspect memory
I'm highly skeptical of the VGA snow explanation. Yes the viewpoint is an early ET4k card but I've never seen this behaviour before
I've seen almost this exact behaviour with an IBM EGA that had bad 4x16 chips soldered to it. It also passed the checkit VRAM testThe $50,000 question is if those artifacts stick where they show up. If they look like "snow", IE, transient flickers with only the duration of a frame then RAM being bad seems really unlikely to me. Is the theory that data is getting corrupted when it's written to the card (which would imply the artifacts would be stable), or it's intermittently corrupting data read back out, but only when it's the video hardware doing it (because it apparently passed a RAM test)?