Due to the number of boards you have exhibiting the same symptom, based on the fact it's a random problem, and, finally, if by "haven't had any issues with these SSDs before", you mean you have tried these drives out on another board successfully, then, please, proceed as follows:
1. Boot the system into BIOS.
2. Once in the BIOS setup utility, press <F9> to restore BIOS default settings.
3. Reset any customized BIOS settings.
4. Clear all DMI event logs by setting the option to "Enable", which is located in the Advanced/Event Log Configuration section of the BIOS Setup utility.
5. Finally, press <F10> to save the new settings and reboot the system.
Note: Ensure your power supply's 460 W., at least.
2x OCZ Vertex 3, located on the SATA6G channels (Blue)
Could be this: