At one point the world number five, who caused controversy on Monday for turning down the opportunity of a 147 break, scored 300 points without reply.
The fourth frame was more disjointed, but O'Sullivan sealed a whitewash and a meeting with China's Yu Delu.
Mark Williams, defending champion John Higgins, Mark Selby, Neil Robertson and Judd Trump also went through.
O'Sullivan, who already plays a reduced schedule on the tour, spoke of his boredom during tournaments and told BBC Sport how he fills his time.
"I've told my agent to smash out the exhibitions because I prefer playing them to tournaments," he said. "I suppose I'm just a born entertainer. As long as I've got a crowd, it doesn't matter if it's the Crucible or the local snooker club, I still get a kick out of it.
"I get so bored at these tournaments. Maybe they should stick an adult creche here to keep us entertained because I just want to go home now.
"Don't get me wrong because I like Cardiff, but 17 days in Sheffield for the World Championship if you get to the final - I'm already dreading that.
"Today I've had a haircut, I've been in the Chinese, I've been for a coffee, I went to Bill's cafe for a couple of hours, I've had a kip, I went to Marks' and bought a bit of grub. What a day. It's certainly not glamorous."
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Welshman Williams, who beat Norway's Kurt Maflin 4-2, told BBC Radio Wales: "My main aim was to play as fast as I can and stop thinking about stuff I've been thinking about.
"I potted quite a few long ones and made a lot of good breaks.
"Whether or not it'll continue I don't know, but I'm certainly going to go out with the same mindset."
Scot Higgins beat Michael Georgiou 4-1 to set up a meeting with Welshman Michael White, who overcame Liang Wenbo 4-1.
Australian Robertson beat Anthony McGill, world number one Selby defeated Fergal O'Brien, and fellow Englishman Trump beat Scotland's Alan McManus, all 4-2.
Former world champions Shaun Murphy and Graeme Dott went out, beaten 4-2 by Luca Brecel and Marco Fu respectively.
Northern Ireland's Mark Allen ended the hopes of Welshman Ryan Day, winning 4-1 to set up a meeting with England's Barry Hawkins.
Ronnie O'Sullivan produced a sublime display to thrash Jimmy Robertson 4-0 and reach round four of the Welsh Open.