Today in Tech: Google+ hits 100 million monthly users by JP Mangalindan @FortuneMagazine September 18, 2012, 9:29 AM EST E-mail Tweet Facebook Google Plus Linkedin Share icons HP tries to go “sleek”; Jack Dorsey’s Square worth $3.25 billion. Square finally closes $200 million round at a $3.25 billion valuation [ALLTHINGSD] In an interview several weeks ago, Square COO Keith Rabois said that the company plans to start marketing itself aggressively. It already has commercials on TV, and a wide-ranging deal with Starbucks announced last month will also help. Starbucks said then that it would invest $25 million into the company, and start using the funds to process all of its debit and credit transactions in the U.S. Starbucks will also allow its customers to pay for their lattes using Square’s consumer-facing app. H-P tries on a sleeker look [THE WALL STREET JOURNAL] Redesigning its devices is more than just a cosmetic project. Revamping the PC division, which is H-P’s biggest business and accounts for about 30% of its revenue, is critical to the turnaround Ms. Whitman is trying to pull off at the Palo Alto, Calif., company. In H-P’s most recent quarter, PC revenue fell 10% from a year earlier to $8.6 billion while the unit’s operating income tumbled 27%. Overall, the company reported its biggest-ever quarterly loss. Apple closes at a record $699.78, 22 cents shy of $700 [FORTUNE] Although the stock is up nearly 75% over the past 12 months, the company is still relatively cheap by the standards of the S&P 500. Apple is sitting on a bigger cash hoard ($117 billion) than any company in the world, and the 60% growth rate its earnings have racked up over the past 5 years can hardly be compared with the S&P 500′s -1.66%. AMD CFO Thomas Seifert calls it quits, Devinder Kumar takes his place on an interim basis [ENGADGET] Advanced Micro Devices’ Senior VP and Chief Financial Officer, Thomas Seifert, has decided to leave AMD three short years after joining the company. As you may recall, Seifert briefly took the reigns of AMD asinterim CEO in early 2011, until the firm found a permanent replacement in Rory Read later that year. No word on why Seifert has decided to depart the chip maker — other than “to pursue other opportunities” — but we do know that Devinder Kumar, AMD’s current Senior VP and corporate controller will replace him on an interim basis. The full announcement awaits in the PR after the break. As predicted, Google+ passes 400 million registered users, now has 100 million monthly active users [THE NEXT WEB] Yet the real story here isn’t the 400 million number, but the 100 million one. Google+’s main competitor Facebook doesn’t even bother talking about registered users because it know the number is meaningless. The social networking giant only talks about monthly active users, of which it has 955 million as of June 30. Both Facebook and Google are talking about combined desktop and mobile users.