Isn't the MediaGX supposed to have all the VGA and SB16 functionality in the CPU itself rather than the chipset?
Those artifacts look like bad video memory, which in the case of the MGX should be carved out of the board's RAM.
Did you try using different memory sticks or toy with memory timings in the BIOS (if exposed at all).

wbahnassi wrote on 2026-05-23, 08:27:

Isn't the MediaGX supposed to have all the VGA and SB16 functionality in the CPU itself rather than the chipset?
Those artifacts look like bad video memory, which in the case of the MGX should be carved out of the board's RAM.
Did you try using different memory sticks or toy with memory timings in the BIOS (if exposed at all).

There's no options for memory timings, just ones for system cache and video bios caching (set to the default settings). I haven't tried different RAM yet, will have to dig for some EDO sticks. I think you're right about the integrated functions being on the CPU itself

That was it! Bad RAM! I looked through my whole collection and managed to find a good pair of 32mb modules. It turns out both original modules were bad. 64megs has never felt so sweet.

Thanks for the help!

Great to hear! I heard those MediaGX CPUs act like glorified 486s... didn't get to play with them for too long though..

This morning I figured I should run memtest86+ just to be safe, turns out even these "good" sticks are producing a ton of errors. No graphical corruption, but it's unstable when trying to run anything in Windows. I think new RAM is in my future...

look over all the simm socket pins with good light and magnification

The slots look fine, and I cleaned the SIMMs themselves with alcohol. I also tried swapping the order of the sticks and it's still failing. I think out of the 4 modules I have on had, only ONE works properly. Two of them are intermittent, and one causes artifacts on screen.

What speed are the ram sticks? IIRC, the mediaGX cpu runs the sticks at different speeds based on the cpu mhz. Try lowering the cpu speed and see if that clears your problem (or test the memory in another pc with known in-spec memory bus speed). If so, faster memory likely will solve your problem .

I run 100Mhz memory in my Cyrix GXm to bypass this issue. What Mhz does your cpu run at, and what speed rating is your memory?

It's a 166mhz CPU, and I'm not certain the memory frequency. The BIOS of this machine is really locked down, no CPU speed options, no physical turbo switch, no RAM timings, etc.

I unfortunately don't have another machine to test memory with, and this Cyrix is the oldest PC I have. Everything else I own is using SDRAM.

Oh I apologize, mine is the later 233mhz version with sdram, so my experience might not be relevant.

So I went digging through my spares box once again and found a single 16mb EDO module.

Turns out installing it alongside my known good 32mb module gives me... 16 megs of free memory. Yeah I know you're not supposed to mix and match module sizes, but it actually passed memtest in this configuration! It's not much, but it'll get me through until I can buy some new SIMMs.

Oh, and Windows works too. My plans to hotrod this rig might have been de-railed by the ram, but it is really funny seeing a PCI Banshee in device manager alongside a Cyrix GX chipset

I also use a Voodoo Banshee in my GXm (300 MHz) build.

I noticed at the start of this thread you were using the onboard video. Was that just for initial testing, or are you doing a dual display configuration?

feipoa wrote on 2026-05-24, 09:22:

I also use a Voodoo Banshee in my GXm (300 MHz) build.

I noticed at the start of this thread you were using the onboard video. Was that just for initial testing, or are you doing a dual display configuration?

I was using it for troubleshooting purposes. I've been trying to get this system to play nicely with POD Gold for the last year, more or less. I know that game is a nightmare to run on most hardware and I have a capable PIII rig that runs it flawlessly, but having it consistently lock up this particular machine forcing a hard reboot has become a challenge I want to solve, or at the least close the door on if it can't be solved.

So I figured trying different video cards (I have a PCI Rage XL card I use for testing motherboards) would be a good start. That's when I realized the onboard VGA was artifacting like crazy, and I made my post here.

(And even after fixing the memory errors and trying different video cards and rendering modes, POD still crashes about 5 to 30 seconds into a race. Sigh...)

Oh and in case anyone is curious, here's some Quake timedemo results. Really not terrible all things considered...