RAID controllers - Whats the difference?

[ChemicalKicks]

So like many i'm redaing these forums and come across PCI RAID controller cards and onboard RAID being discussed.

I've heard comments like "RAID uses X amount of bandwidth, ive got 5 HDD's so PCI is better" HUH *scratching head*

Also heard people mention that if you are using a PCI card when it comes to MOBO upgrade time it helps, but how? And what would happen if you didnt have a card?

So which is better onboard or PCI card?

 

[ChemicalKicks]

PCIe gives you 250Mb/s per lane so 250Mb/s for a 1x slot, 1Gb/s for 4x etc. PCIe gives plenty of bandwidth, especially with 4x & 8x cards but you need a mobo with enough lanes/slots to support these.

Cool.

Next questions then. When you say PCIe give 250Mb/s per lane does that mean that you need 1 card for every HDD? Or if you dont need one card for every HDD by adding more HDD's to the one card does that mean the total bandwidth is shared between the HDD's?

Reason im asking is because im thinking of setting up RAID0 with 3 HDD's and want to get the best performance.

 

[ChemicalKicks]

To be honest, for a 3 disk RAID0 array I'd be sticking with an onboard controller if you have one.

Your response has helped clear things up, so final question would I see a performance increase from using a PCIe card with 3 compared to 3 using onboard?

 

[ChemicalKicks]

So would, lets say any IP35 MB provide a PCIe bandwidth on the raid/sata ports?

Therefore no performance increase in card?

 

[ChemicalKicks]

Thanks rpstewart.

Was going for the abit Pro.