Guy,
Today I have an smart switch and a RB45G .
If I by a CRS125-24G-1S-RM can I replace both for this cloud switch/router ? as I see, this peace of art is a switch and a router te same hardware, is this correct ?
heers
How much traffic do you need to nat?
It is a small office, no more then 20 estatiina connected.
Why?
To know of this routerboard can handle it.
You will not experience any problems with this router board.
The routerboarden have a very good performance.
In theory, yes, they both use the same family type of CPU only a little bit slower clock-rate (and a bit different chip specifications). But 680Mhz vs 600Mhz isn’t that much of a difference. Then again, I have heard the CRS125 is not AS FAST as say an RB2011 at everything because it’s meant to be a switch, but I don’t see a technical reason why this would be true.
In reality I believe it will work fine. I have used a CRS125 up to 100Mbit (very light config) or 50Mbit (Queues, etc.) without problems.
Final answer, should be no problem at all. 
Don’t use many firewall and routing rules.
This is hard to handle for the some light cpu.
I have one and are verry satified with his performance.
I use it for nat 2 ISP to 3 networks
Thanks guys!
Cheers