Router speed

Hello. I have a question about router speeds, I want to upgrade my cable package which includes 1000mbs (up to). My router/modem is a netgear c6300 which I installed the other day.  What I need to know is this: my Netgear c6300 will do speeds up 325mbs. If I upgrade my internet package, do I need to buy a new router/modem that says it will use speeds up to 1000 mbs or can I keep my Netgear and it will only use speeds up to 325mbs?

Thanks in advance