Here is a VM you can download that will allow you to test the load on a router or multiple routers with a full IPv4 Global BGP table of over 500,000 routes.
Put 500,000+ BGP routes in your lab network!!! Download this VM and become your own upstream BGP ISP for testing. | StubArea51.com
We put the full feed in a MikroTik in our lab as well as a Cisco router in GNS3. It doesn't connect you to the Internet obviously and I wouldn't use it in a production network, but you can test things like:
Setting BGP Attributes
Cisco was my first networking love, but my "other" router is a Mikrotik...