Intel has a new explanation for the famous scowling "Phelps face" from last summer's Olympics – inadequate processing power. That's the basis for a new series of ads pairing the world's fastest swimmer with the world's slowest computer, and with Jim Parsons of "Big Bang Theory" and Intel fame.

Mr. Phelps' scowl was originally captured on camera as his rival Chad le Clos of South Africa warmed up by shadow boxing in an apparent effort to distract or intimidate him before August's 200-meter butterfly competition in Rio. Mr. Phelps won anyway, and the face became a social media meme.

Intel hopes to ride some ripples from that #PhelpsFace wave in new ads from McGarryBowen breaking online this week and on TV Oct. 17 during "The Late Show with Stephen Colbert" on CBS. The new ads back Intel's recently launched Seventh Gen procesor.

The idea originally came during a different Olympic moment, said Intel Chief Marketing Officer Steven Fund, when Mr. Phelps was "watching himself swim, looking at the image through a very old computer. And we came up with the idea of the world's fastest swimmer on the world's slowest computer."

Intel reached out to Mr. Phelps through his agent during the games, shot the ad and related social media content shortly thereafter, and, Mr. Fund said, "Got on air I think before anyone else has done anything with him post-Olympics."

Mr. Phelps was already a fairly prolific endorser for, among others, Under Armour, Omega and 800razors.com (an online razor retailer he's also an investor in). Mr. Fund, himself a former global marketing director on Procter & Gamble Co.'s Gillette, saw him as a good fit for Intel as well.

The message is basically the same one Mr. Parsons has been delivering: It's time to upgrade your computer. And Mr. Parsons has been so effective, Intel had no interest in walking away from him for the new ads either.

With a PC processor market share of more than 87%, something that beats even his alma mater Gillette in razor blades, Intel's primary focus is growing the PC category rather than market share, Mr. Fund said. Over recent years, people have been waiting longer to replace old PCs, he said. "But actually this past year PCs have stabilized, and there was in fact just data published by IDC that shows PCs have grown for the first time year over year."

Indeed, both IDC and Gartner data showed the North American PC market growing in the second quarter after five quarters of declines.

"I'd like to say most of it is the marketing," Mr. Fund said. "The Parsons campaign is our best advertising ever. We test everything at Intel. It's got great breakthrough. It's very clear on message, and persuasion metrics are very strong."

He declined to disclose spending, but said the new Phelps-Parsons effort will get significant weight both online and on TV. Intel's in-house Agency Inside has joined McGarryBowen in creating social content for the broader effort, with OMD handling media.