How can I get a high sampling rate in USRP on GNURadio

Hi all

I want to transmit samples as fast as I can. However, my maximum
sampling
rate is only 5MSps because of some congestion in my CPU, and I want to
get
the rate at least 10MSps.

I use Ettus USRP N210, and processor of my desktop is Inter Core
i5-3570,
and memory is 16GB RAM, and ethernet card is Realtek RTL-8169.

Can somebody tell me how to get high sample rate?

-Juhwan