From my personal expericence with all kinds of embedded computers (RPI, Panda, Cubieboard, pcDuino, Olinuxino and so on), these have some limitations that make them not the perfect choice for running a full node, especially when it is a POS or POB node:
1. Memory
2. Wearing out the flash based harddisks

Without staking and just little burning, my Slimcoin node uses ~700GB of memory. I suspect while synching up this amount is noteably higher. The Raspi 3 has 1GB memory AFAIK, if you also run a graphical desktop on the same device that won't just cut it and swapping to an SDcard maybe is suboptimal as well. Right now, while replying, my browser uses ~2.8G memory.

If you have coins in your wallet, you might want to try to synch up with an empty wallet and see if you get any further that way. Also quitting all memory-intensive programs like browser and such could help (if you do you run an graphical desktop on it). Then once it crashes, check your syslogs for messages about the OOM killer ("Out of Memory: Killed process XY").
But in the end I do not think that any kind of device with under 2GB (better 4GB) of memory and a fast storage medium will be able to run a full node of Slimcoin in the long run.

HTH