No difference whatsoever... well, maybe a couple points in burst speed, but nothing you could notice except in a benchmark. No hard drive can get close to 150mbps that SATA'1' has, so SATA2's 300 is all marketing hype.

Mike.

It won't make any difference at all. The only way SATA and SATA 2.0/2.5 will make a difference is when you are running a RAID system.
After 2 SATA drives in a RAID 0 system, you will begin to approach the SATA 150 theoretical limit.

Read this for more info:
http://www.seagate.com/docs/pdf/whitepaper/TP-539.pdf

Yes, the mechanical part of the HDD is the bottleneck. However, increasing the rotational speed of the HDD causes some issues to arise: 1) temperature increases, hence the need for active fan cooling for raptor drives, 2) shorter life span of the drive.

Next year (I think) the latest advance will come - perpendicular recording. This will help alot in the performance sector and I think we'll actually start to see some actual real life increases.

As for the Port Multiplier, just because a motherboard has 4 SATA ports, doesn't necessarily mean that it supports 150MB/s on each one. I think the port multiplier here means 1 SATA channel, but which is split between 4 drives, in the case of the white paper. The RAID 0 in the white paper is saying that when 4 drives are run in RAID 0, then the single SATA 3.0Gb/s channel is starting to become saturated, since each drive is 60MB/s, for 240MB/s. 1.5Gb/s is really 187.5MB/s. So we can see that 4 RAID 0's on SATA 150MB/s is overwhelmed at that point.

Now that we have single core CPU that approaches 4 GHz and dual core at 3.2 GHz per core with quad core coming soon, coupled with RAM running at 677MHZ dual channels, at this point, the bottleneck is the hard drive. I think with more and more people use their PC for multimedia including PVR, drive and motherboard manufacturers should pay more attention to the bandwidth of the harddrives. I have a RAID 0 with 2 SATA 150 drives in my system and it's still not fast enough when transfering video files. When I can find both drives and controllers that are certified as SATA 2.5, I will upgrade for sure.

ftp://download.intel.com/design/m [...] 1001US.pdf
Look at page 28 where it details what SATA chip this board uses.
"As a manufacturing option, the board provides a Silicon Image Sil 3114 Serial ATA (SATA)
controller and four connectors (that support one device per connector) for SATA devices. These connectors are in addition to the four SATA connectors of the ICH7-R/ICH7-DH SATA interface.
The Sil 3114 controller uses the PCI bus for data transfer and provides a maximum data transfer rate of up to 1.5 Gbits/sec."

The controller uses the PCI bus for data transfer, and that gives you 150MB/s bandwidth. Therefore, there are 4 ports on this channel of SATA. So SATA is 150MB/s per SATA Channel, not per port. Every channel can have multiple ports. That is the reason there is a MUX (or multiplexer) in the Seagate white paper. This also makes sense, because no HDD available today that I know of has a burst rate of 150MB/s. Most are in the 50MB/s-80MB/s range. Its a waste, unless you combine 2 or more HDD's in a RAID system.

Even if you had 4 drives on a RAID 0 system on SATA 150MB/s, it would still outperform a single drive since you max out the bandwidth on the SATA bus.

They can tack it on to the PCI bus because the PCI bus runs at 266MB/s these days - depends on the board's clock, 33Mhz or 66Mhz.

P.S. Thats a sweet system!