SATA II on MB or PCI slot - differences?

[tomsoter]

I've read on this site that it's hard to exhaust SATA I capacity currently but I buy a pc about every 10 years so I have to plan for future. Do I need a MB that is SATA II compliant or is SATA II controller on PCI the same?

 

[imported_Kensai]

It would be better to have native support for SATA2 on your mobo, since it'll save you a PCI slot for the future.

 

[Peter]

Storage controllers on legacy PCI are limited to ~95 MB/s _total_ throughput, simply because PCI won't go any faster. This limitation does not apply to those storage controllers that are integrated into the core chipset.

 

[Promethply]

Also most current integrated SATA controllers usually have a dedicated bandwidth reserved for those controllers, while SATA controllers on the PCI has its bandwidth divided among several other devices that are connected to the PCI buss.

 

[Aenslead]

local chipsets have speed up to 1gb/s, so there would be no bottleneck that Peter is telling us about.

 

[furballi]

You will not encounter the speed bottleneck for a long time if you're using an IDE connector or SATA connector on the motherboard. Both can deliver at least 133MB/sec, independent of what you have connected to the PCI/PCI-E slot.

Currently, a very fast hard drive will top out around 75MB/sec, which is well below the 133MB/sec limit.

 

[Peter]

You are dreaming if you think standard PCI delivers 133 MB/s. This'd be the theoretical limit if there weren't any bus arbitration, addressing and other housekeeping - and if that controller were the only device there. It is not. In real life, _storage_ controllers on legacy PCI do not achieve an actual _storage_ throughput of more than approx. 95 MB/s. A striped pair of today's completely average drives hits this ceiling with ease, and at the same time saturates the PCI bus so massively that little else gets done.

Bad move.