RAID0 SSD Samsung 830

Today trying to setup RAID0 2 Samsung 830 128GB and 256GB SSD. When i try to create raid new volume why it only allow 226.6 GB only am i do something wrong?

You need identical drives to set up an array. In your case, it will default to the lowest size available, and treat the array as if it were two 128 GB drives.

But, I can save you time and grief. Don't bother. Use the single 256 as your primary drive. RAID0 is all hype and myth for 99.9% of the people using it, and actually can negate some of the benefits of an SSD. When SSDs first came out, system builders were striping them together to make up for their small size. Now that prices have fallen and capacities have risen, there's no reason at all to consider a RAID0 array with SSDs.