Probably correct, though I think I had a 486 board with an AGP slot? I didn’t have anything newer than that until the Core 2 Duo came out.

AGP came too late for the 486. It may have been VLB, a short-lived step between ISA and PCI (and then AGP).

I just looked up a few old motherboards and I think you are correct! I remembered it was a brown PCI-looking bus and incorrectly assumed the only thing that matched was AGP - the VLB looks exactly like what I remember.

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