Lots of inconsistent info in this thread...
RAID0 will theoretically double your reads and writes, with absolutely no data redundancy and increased risk of data loss. If you lose one drive, your very likely to lose ALL your data. RAID0 will also double your storage capacity, so two 512GBs in RAID0 will give you a whooping 1TB capacity. RAID0 isn't even technically a true RAID, as RAID stands for a redundant array of inexpensive drives, and RAID0 offers no redundancy, only performance. (Hence the 0)
RAID1 will provide you with data redundancy, while maintaining only 512GB across both drives. Write speeds will be the same, possibly even slower than with one drive. However read speeds from a RAID1 can offer some increased performance, as you have two drives available to queue. This really is more significant with mechanical HDDs though, and does not offer you anywhere near the performance of a RAID0. However you will have data redundancy.