Carlo Ancelotti's side were at their devastating attacking best at the Riazor, with a Gareth Bale double, James Rodriguez's first Liga goal and a late brace from Javier Hernandez supplementing Ronaldo's treble.
Defeats to Real Sociedad and Atletico Madrid had put Ancelotti under some pressure, but after a morale-boosting 5-1 UEFA Champions League win over Basel on Wednesday, Real never looked like falling to a third straight domestic reverse this weekend.
They went in three to the good at half-time courtesy of two goals from Ronaldo that sandwiched Rodriguez's superb strike.
Deportivo were given a way back into the contest right after the break as Haris Medunjanin confidently converted a penalty following handball by Sergio Ramos, but Bale restored the three-goal cushion with 24 minutes to go.
Bale doubled his tally in the 74th minute and Ronaldo completed his hat-trick soon after, before on-loan Manchester United striker Hernandez came off the bench to add further gloss to the scoreline after Toche had grabbed a consolation for the hosts.
Deportivo coach Victor Fernandez was wary about reading too much into Real's poor Liga form before Saturday's meeting, but it took the away side 29 minutes to go in front.
Alvaro Arbeloa fired an inviting cross in from the right and, although the delivery forced Ronaldo away from goal, the Portuguese sent a fine looping header over German Lux.
Real's second followed just seven minutes later as Rodriguez opened his Liga account in style, curling an unstoppable drive into the top-right corner from 20 yards, before Ronaldo effectively wrapped up the win with his second before half-time.
Benzema found himself felled by Lux about 30 yards from goal and, with Deportivo expecting a free kick to be awarded, Ronaldo coolly stroked into an empty net to give Real a commanding lead at the break.
Deportivo were given a lifeline right at the start of the second half as Ramos appeared to handle an Isaac Cuenca header in the area and Medunjanin nonchalantly dispatched the resulting penalty.
The hosts looked inspired during in a 15-minute spell immediately after half-time, yet they were unable to make the most of their improvement as Bale squeezed an effort past Lux following a clever pass by Marcelo.
Bale added the fifth from a similar position in the left side of the area after a good run from Isco, and Ronaldo grabbed the sixth and his hat-trick with 12 minutes to go, hammering home after Rodriguez pounced on sloppy defending by Sidnei.
Deportivo grabbed a late consolation as Toche nodded in at the near post, but Real were still not done.
Hernandez, who replaced Bale with 13 minutes to go, first scored a ferocious half-volley from the edge of the area before seeing another long-range effort deflect beyond Lux to make it the first time in Real’s illustrious history that they have scored eight away from home in a La Liga fixture.
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