Some help please!

i have a database with 85.000 news, and i am creating a new webiste,
to avoid some server load, i will separate the news, the latest 1000 news will be at the live webiste and the other 84.000 news will be on a sub domain, called
wanted to ask if this will affect my alexa and google ranking, if yes, what can i do to improve or let them as they are.

Best Regards