Not being an expert of any kind. But I think that its related to the SSD
Reading a little on a few forums, other people have reported spontaneous reboots with no BSOD http://forum.crucial.com/t5/Solid-State-Drives-SSD/RealSSD-C300-Random-reboots-using-AHCI-IDE-is-OK/td-p/36852
Also as they mentioned in the thread, maybe its a dodgy SATA cable (Linus ones had a SSD problem because of a dodgy SATA cable, can't remember what his issue was though)
Or it may just be a firmware conflict between the SSD and motherboard
If it is not SSD related the I think its the ram Could you say exactly what motherboard, and SSD you are using (Firmware and BIOS version could also possibly help, but don't know) And maybe also try to swap the SSD with a spare HDD to see if it keep rebooting.