Apple Inc. had a rough back-to-school season in personal-computer sales, while Alphabet Inc.’s low-price Chromebooks were a big hit for students, according to two third-party analyses released Tuesday.

International Data Corp. and Gartner Inc. reported tabulations of PC sales for the third quarter Tuesday, and both analyses showed huge drops for Apple’s AAPL, +1.57% Mac sales in the important back-to-school quarter. IDC tracked a 13% decline for Apple from the same quarter a year ago, while Gartner reported that Mac sales dropped 13.4%.

Chromebook sales told an opposite story, which is revealed in the difference between the two studies. IDC includes Chromebooks in its recording of PC sales, and said that PC sales overall declined 3.9% year-over-year, a better performance than the firm expected. Gartner, which does not count Chromebook sales with its PC numbers, recorded a more drastic 5.7% decline.

“While our PC shipment report does not include Chromebooks, our early indicator shows that Chromebooks exceeded PC shipment growth,” Mikako Kitagawa, principal analyst at Gartner, said in a news release.

Chromebooks, Alphabet’s GOOGL, +2.07% GOOG, +2.39% stripped-down PCs that run on Google’s Chrome operating system, have become popular in the education market because they offer basic computing services, such as word processing and internet browsing, at a low price. Apple’s Mac offerings come at a much higher cost to consumers, and offer the ability to perform more intense tasks that may matter more to professionals than students.

“Chromebooks had another banner quarter in the K-12 market,” IDC reported in its news release.

Apple has not refreshed its Mac lineup much this year, but has released the iPad Pro aimed at education and professional markets, a device that was not counted in either survey. IDC analyst Jay Chou cited those as larger factors in Apple’s decline.

Apple “hasn’t seen some of its major product lines refreshed in some time, and the fact it did quite well through 2014 and much of 2015 also lends to poorer year-on-year comparisons in the absence of new major products,” Chou wrote in an email. “Some volume was also taken with the introduction of the iPad Pro (which is not counted as a PC by IDC) which was good enough to be a PC substitute for some people.”

Bloomberg reported this summer that Apple plans to release refreshed PCs as soon as October. Apple will release Mac sales results in its quarterly earnings report scheduled for Oct. 25; that date was changed from Oct. 27 “due to a scheduling conflict,” according to Apple, and some blogs have speculated that Apple will schedule an event highlighting new Macs on that date.

Chromebooks are manufactured by all the top PC companies except Apple: Lenovo Group Ltd. LNVGY, -1.63% , Hewlett Packard Inc. HPQ, +0.54% , Dell Inc. and Asustek Computer Inc. AKCPF, were the top five manufacturers by market share along with Apple, according to both reports. Other Chromebook manufacturers include Alphabet, Samsung Electronics Co. Ltd. 005930, +0.68% and Acer Inc. 2353, +0.59% , which Gartner said was in sixth place.

While Lenovo maintained its crown as the top PC manufacturer, its lead over HP narrowed in the third quarter, both studies found. IDC reported a near-tie between the two companies, with Lenovo holding 21.3% of the market and HP at 21.2%, up from 19.7% in the same quarter last year. Gartner’s Chromebook-less report had Lenovo at 20.9% and HP at 20.4% but also tracked a big jump for HP, from 18.8% in the third quarter of 2015.

Both studies also showed continuing consolidation of the PC market as those top manufacturers grow more dominant. IDC said the top three vendors controlled 58% of the market in the third quarter, up from 55% a year ago and 51% in 2014; Gartner noted the top six vendors in its survey enjoyed a record 78% of the market.