I'm testing a 440EX system which normally has a maximum memory limit of 256MB but will accept 512MB with two 2RX4 (dual rank) sticks. The issue I'm having is that Windows 98 becomes unstable with this combination but only when I'm running games.

I get different stability and anomalous results depending which card and which driver I use but all problems go away with anything less than a single 256MB stick in any combination of the two available slots.

I've tested several 2RX4 sticks and the problem is consistent no matter who made the chips on it, suggesting that the problem is not defective memory.

Running Memtest86+ does not produce any errors. As mentioned previously, I only have problems when I run games but these are the only tests I've run at all. Are there any memory stress tests for Windows 98 so that I can take the video card out of the loop? Something that can verify itself rather than just a benchmark which may ignore any errors would be ideal.