Hey B,
Who knows when the nForce 615 & 620 chipset mobo's will appear on the market. They have had working chipsets since before May 2002. I don't know when they will be shipping the chipsets to mobo manufactuers, & when the mobo makers will be designing & using the chipset in their own mobos.
As far as pricing goes, the nForce 615 should be close in price to the KT400, & the nForce 620 should be about $30-$40 more.
As far as telling you which one that I like.............let me first say, I don't mind tweaking my own computer for very small percentages in synthetic benchmarks. Having said that I would most likely get a KT333 mobo like the one I have: a MSI KT3 Ultra ARU. I cannot at this time see getting a KT400, because I do not see a big advantage of having a 8X AGP slot. I would still be using my EPoX 8KHA+(KT266A chipset), but my good friend got me this MSI KT333 mobo for Christmas & I had to use it(not that it isn't a good mobo, the KT333 is not a big performance gain over the KT266A, & the KT400 has no performance gain over the KT333).
If I was making a system for someone else, I would most likely get a nForce 620 mobo, just because it is a great value for someone who doesn't need the fastest video card every 6 months. Most people tell me it is much more stable than any Via chipset...........I don't know about that as I have not built a system with a nVidia chipset yet. Next month I am going to build a budget system with the nForce 415 or 615 chipset & I'll tweak it for a week before delivering it.
If you post why you need a new mobo & what you plan to use it for, I will give you a better answer. Good Luck in your choice.
Peace Out...................tile
god knows your entire system setup & he would answer your questions if he could just stop laughing