I tyested the drives with full read, full write and then full test with the Intel SSD Toolbox. Both drives came ot ok.
As for testing performance, I was only getting ~1200MB/s, then I realized the CPU was an Sandy Bridge i3, so I only had PCI-Ea, so Iswapped it for a IB Xeon to get PCI-E 3 speeds. After this the computer froze mid-boot and then did not boot at all. The motherboard is a X9SCL (no IPMI). After powering up it beeped 18 times. I removed all cards, RAM and drives, and got a memory error (5 short beeps, 1 long beep). I put back the RAM and now I get 6 beeps. Resetting the BIOS did nothing. 6 and 18 beeps are nowhere to be found for Supermicro beep codes.
I was afraid my "new" drives got damaged, so I took the CPU and put it in another X9SCL and it started correctly and the drives were now working @PCI-E 3 speeds. One drive reaches 2600MB/s, the other one ~2200-2300MB/s for reads.
What could have happened to my other board?
Edit: Forgot to mention, the P3605 are bootable on the X9SCL, I guess it'll be bootable on the X9SRL-F and the X10 boards too. I'll try later.