The ASRock X79 Extreme9 has
"4 x SATA3 6.0 Gb/s connectors by Marvell SE9172, support RAID (RAID 0 and RAID 1)" -
http://www.asrock.com/mb/overview.asp?Model=X79%20Extreme9&cat=Specifications However, I question them as being 'bootable' ; see ->
http://www.hardocp.com/article/2012/02/09/asrock_x79_extreme9_lga_2011_motherboard_review/3 Read the Marvell SE9172 + Intel caveats.
Quote
"In that regard it’s just like the 9172 controllers. The difference is the 9172’s can be used as bootable controllers outside the OS provided that the Intel controller is in legacy IDE mode or AHCI mode only."
Otherwise, there's no other onboard RAID 0
x4 SSD/HDD options for SATA3 boot drives on any LGA 2011 MOBO's that I can think of anyway, just
Intel SATA2.
Never cross chipsets for SATA e.g. Intel + Marvell = BAD!!! Even though you 'could' use Windows to create a RAID 0 with (Intel + Marvell = BAD) don't do it and it won't be bootable.
There won't be that much of a difference (real world) using the Intel SATA2 ports for a RAID 0 w/4 SSD's. Most of the 'real world' and relevant IOPS is from 4KB R/W. However, with a risky RAID 0 with several drives
'if 1 fails they all do' then IMO a RAID Card is a smart move and will be significantly faster.
Ideally, use a Dedicated RAID Card e.g. LSI x4 or x8 PCIe card + Kit + IMO batter back-up with Cached cards:
LSI MegaRAID SATA/SAS 9260-4i -
http://www.newegg.com/Product/Product.aspx?Item=N82E16816118107
LSI MegaRAID SATA/SAS 9260-8i -http://www.newegg.com/Product/Product.aspx?Item=N82E16816118105
Just make damn certain your MOBO is 100% compatible!
-- edit
Example options (Battery Backup and FastPath)
http://www.lsi.com/channel/products/storagecomponents/Pages/MegaRAIDSAS9260-4i.aspx