As someone who owned an nForce, ALi Magik 1 and KT266A I can tell you all these boards perform about the same. For me, the KT266A has performed the best and is what I'm using today in the form of an Abit KR7A-RAID. The nForce is extremely picky about memory and the memory I chose to run with my nForce wouldn't work (OCZ PC2400 CL2) with my MSI K7N420 Pro but it works great in my KT266A.
I like the concept of the nForce a lot more, though. I mean, it's NVIDIA for crying out loud - I wanted to support them in whatever way I could. But my MSI nForce was a pretty big disappointment.
Is a kt266a ddr333 friendly?
You tell me. Names of VIA chipsets typically follow the types of memory and bus speeds that are supported at the given time. DDR333 should
be compatible with a KT266A board, but it won't run at nearly the stock spec. If you plan on keeping your board (which you still can as the KT266A is still a viable chipset for gaming and so forth) pick up some less expensive Crucial PC2100 DDR. That would be a better band-aid fix until you save up enough cash to grab yourself an nForce2 or whatever other chipsets come along that support AMD's 166 MHz processors. Or, hold out even longer for the Hammer. A KT266A chipset will do just fine for at least another 8-12 months.