I have been searching within the forums and I have read - https://wiki.mikrotik.com/wiki/Manual:BGP_HowTo_%26_FAQ#Question:_How_much_memory_is_required_to_keep_the_global_BGP_route_table.3F - in order to find out how many how many IPV4 routes can CCR1072-1G-8S+ hold?. I saw here - http://forum.mikrotik.com/t/ccr1072-1g-8s-max-number-of-routes/118270/1 - that someone said that their 1072 supports 2 million routes and it handles it without a problem. I comparing it with a Juniper MX5 router and I need CCR1072-1G-8S+ to use 3 ISP, all of them announcing full (or close to full) routing tables.
The 1072 is quite old. Would not recommend it. All CCR10xx only does software routing, hence there is no real upper limit (except for memory) CCR2116 is a better choice.
However, No Mikrotiks can hold million of routes in hardware. Not sure what a MX5 does but probably more, since a couple of factors more expensive.
Approximately each entry occupies 512bytes.
For about 1,000,000 routes, roughly the size of the Full Route Table now, you need roughly 512Mbytes per table.
With 3 different BGPs, that’s roughly 1536MB of memory used.
The CCR1036-12G-4S, that have 4GB of RAM, does it perfectly without problems (it only acts as an Edge Router)