Pci-X or PCI-express, Future Mobo trends

A mobo philosophical question. I need help/advice. I have watched as PCI-X boards became closer to atx size workstations in terms of design (e.g. with agp 8x) - just recently, before the latest new intel chipset release, Gigabyte and Supermicro released boards with a tweaked or different intel southbridge called "enhanced Rapids" (although I can never find mention of it on intels site) to give them the full functionality of a typical intel875 chipset workstation BUT with SCSI 320 and/or PCI-x slot/s running at 66 MHZ (I wanted 133MHZ   ).

I thought I was dreaming, as I have greatly desired a typical or mainstream ATX sized board that has either onboard SCSI 320 and/or PCI-x at 133 MHZ. Basically I want the fastest IO possible for a system to run with an ATX size and all the extras (firewire, AGP etc..). (There aren't many mobos on the market with Pci-X and something like AGP however Tyan has also been moving in that direction.)

However, I fear that with the new PCI-"express" release/focus from Intel that mainboards will continue to be limited to no more tham SAT Eide drives bandwidth(boring). I am NOT an expert or even a novice at undrstanding how bandwith works on different areas of a board, nor do I know or understand if intels claims that the new PCI-express format has less latency, overhead etc than PCI-x is accurate or not.

I have the money (or credit) to spend (well, atleast I like to pretend), but my question is.... Am I wrong to imagine that the ultimate performance mobo (for anything I want to do including video editing) would be an ATX size typical mainstream "features" mobo WITH the ability to run SCSI 320 (15k rpm) drives on a bus (e.g. pci-x at 133 Mhz) would be a performance nuts dream (i like the idea of seeing a 1-2 second boot up time)?? I didn't think PCI-"express" bandwidth would come close to supporting the bus width needed to fully utilize a scsi 320 drive/s? Or do I simply not understand bandwidth issues well enough - please, looking for a chalkboard explanation of why I may be right, or why I am wrong/just silly, and... to better understand bandwith data rate up and down the entire mobo bus.

Is, for example, the new PCI-express bandwidth so great that all the bus is affected (or just the former AGP bus)? Can it handle SCSI 320 theoretical peak transfer rates (once/if adaptec makes a card for PCI-express)? Am I crazy for thinking I need that anyway and should I just setlle for SAT drives and their corresponding data rates? Anyone can enlighten me or respond to my continual dream machine?? Is it time to put PCI-express with SAT drives versus PCI-x with SCSI drives just to see how great the perf. difference really is (and whether it's worth the cost difference or even mobo design)??

Thanks for your time and help.

<P ID="edit"><FONT SIZE=-1><EM>Edited by DrJohn on 08/04/04 01:53 PM.</EM></FONT></P>