For sale is a rather rare I-O Data PK-X486S50-3 upgrade card for PC-9801 series computers, that will also likely function in Tandy 1000 systems. The other switches are not used. I can send PDF link to drivers, such as as the PK-486S50 Enable cache tool (also available on GitHub), the IBM486 cache driver, and original I-O DATA "Power Up Kit / PK-X486S" series drivers disk image.
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