Honestly, it is unexpected that MicroRAM Rev 1.2 crashes or freezes irregularly not only in XT-IDE, but also in Area 5150. Even the 5150 Rev.A (16KB-64KB, Rev.0 04/24/81) motherboard I have is cumbersome, but after a temporary replacement with Rev.2 10/27/82 BIOS for testing, SW2's RAM I need to change the setting from 544KB to 640KB. It wasn't just one, both did such a tedious job. MicroRAM Rev 1.2 continued to cause problems even after testing on two 5160 motherboards, so it was forced to test on two 5150 motherboards. there wasn't FYI, I also tested MicroRAM Rev 1.2 with two instead of one. In Rev 1.0, which I purchased several years ago, and Rev 1.1, which I purchased several months ago, nothing happened. There were no problems. If it had collided with the Area 5150, I would have thought it was a compatibility problem, but It crashed even in XT-IDE, so I was able to confirm that it wasn't an issue with the Area 5150.