Windows 10 hasn't proven to be the PC industry's knight in shining armor... at least, not yet. According to a report from research firm International Data Corporation (IDC), computer shipments fell 10.6 percent in the fourth quarter of last year, resulting in the steepest year-over-year decline in history.

Rival firm Gartner reports slightly better figures with a drop of just 8.3 percent. For the year, IDC estimates shipments declined by 10.4 percent while Gartner reports an eight percent drop. In real-world terms, it means that fewer than 300 million PCs shipped during 2015.

Update: There was an important remark within IDC's report that we missed earlier. As reported by PCWorld and a few other outlets, high-end gaming desktops and laptops are not on the decline but represent the fastest-growing PC segment. This partly explains why we've seen major manufacturers like Lenovo, Dell/Alienware, Asus and Acer catering to the gaming market. As interpreted by IDC analysts, the PC gaming crowd is not as price sensitive as the mainstream or business PC market, they upgrade sooner, and often build their own PCs. Along with high-end and gaming PCs, sales of all-in-ones are doing pretty well apparently.

Preliminary Worldwide PC Vendor Unit Shipment Estimates for 2015

(Thousands of Units). Source: Gartner, January 2016

Company 2015 Shipments 2015 Market Share (%) 2014 Shipments 2014 Market Share (%) 2015-2014 Growth (%)

Lenovo

57,123

19.8

58,956

18.8

-3.1

HP

52,551

18.2

54,996

17.5

-4.4

Dell

39,159

13.6

40,499

12.9

-3.3

Asus

21,198

7.3

22,671

7.2

-6.5

Apple

20,741

7.2

19,598

6.2

5.8

Acer Group

20,340

7.0

24,015

7.7

-15.3

Others

77,624

26.9

92,945

29.6

-16.5

Grand Total

288,735

100.0

313,681

100.0

-8.0

The PC industry had a number of factors going against it in 2015 including continued competition from tablets and large-screen smartphones, longer upgrade cycles, weak international currencies and surprisingly enough, even the launch of Windows 10 (due to its free upgrade model which encouraged existing PC owners to keep their machines around for longer rather than buy something new).

Top Five Vendors, Worldwide PC Shipments, 2015 (Preliminary)

(Thousands of Units). Source: IDC, January 2016

Vendor 2015 Shipments 2015 Market Share (%) 2014 Shipments 2014 Market Share (%) 2015-2014 Growth (%)

Lenovo

57,182

20.7

59,306

19.2

-3.6

HP

53,534

19.4

56,869

18.4

-5.9

Dell

39,049

14.1

41,509

13.5

-5.9

Apple

20,794

7.5

19,575

6.3

6.2

Acer Group

19,680

7.1

24,043

7.8

-18.1

Others

85,997

31.1

107,063

34.7

-19.7

Grand Total

276,216

100.0

308,365

100.0

-10.4

Looking ahead, 2016 is expected to be a little better to vendors. Aging PCs will eventually need to be upgraded, as will those PCs that didn't upgrade to Windows 10 yet. Attractive pricing and new products (like the Oculus Rift, which requires a moderately powerful computer to run) will also help drive sales, as will a larger commercial adoption of Windows 10 before the free upgrade offer expires.

Image courtesy Dylan Tweney, VentureBeat