Correct, of course, Tim. MB, not GB.
VLB didn't really get going properly until after the 486DX-50 was on the way out. For that reason, it was seldom an issue. When the DX50 was around, it was ISA all the way. But don't think that this meant it was trouble-free. DX50s were very troublesome indeed. Dreadful bloody things. (Well, actually, the trouble was that most motherboards just couldn't hack running at 50MHz. The CPU itself was presumably OK.
VLB problems were much more prominent with the 486DX-40, which came out about 18 months later. (By then, VLB had gone from weird but promising new development to full-on mainstream.) The DX-50 was hard enough to get working with ISA, never mind VESA. The DX-40 was fine on ISA but VESA was scary.
The real answer was the 486DX/2-66 which had been theoretically available since six months before the DX-40 debut, but only if you were a successful stockbroker or a Middle-eastern princeling. In practice the DX/2-66 became available to normal people six months after the DX-40. It went from being a mega-expensive Intel-only product to a still pricey but not unreasonable performance chip of choice overnight when AMD brought their one out. At that point you could buy one for a semi-sensible price (Intel or AMD, didn't matter, the price was about the same, as was the performance), plug it into pretty much any motherboard, and expect it to just work. Well, as much as you could expect anything to just work in those days. You often had to fiddle. If you wanted work-first-time, every-time, nothing matched a 386DX-40 until about the time of ... oh ... let's say well into the PCI era. Hell, RAM remained the usual problem child right up until about 2005 or so.
