It will be noticeably faster. RAID0 is faster than a single drive, but still not as fast as an SSD cached drive.
Get a 128 GB when it goes on sale, and use it as a 64 GB cache. Or just get a 64GB Crucial M4. It won't be as fast as a 128GB but almost. That is assuming you have an Intel Z68 or Z77 chipset. If not, you'll need something like the
Crucial Adrenaline.