Transfer from T2 Domestic to T3 international

I have a connection between Air China from Hefei arriving in Beijing PEK T2 at 12:40 and a Cathay Pacific flight to Hong Kong departing from T3 at 16:45.
The connection time is 4 hours and 5 minutes.
Is it enough or should I take the earlier flight from Hefei to Beijing (arriving at 10:50)?
Thank you