IDC recently released their report that predicted a slight decline in the global shipments of personal computing devices (PCDs).

From a total of 435.0 million units in 2016, it is forecast to drop to 418.2 million units at the end of 2021.

All up, this represents a five-year compound annual growth rate (CAGR) of -0.8 percent.

The forecast comes on the heels of a stronger than expected showing for traditional PCs in 2016, largely put down to a combination of aggressive promotional activities in the second half of the year and tightening component supply for notebooks, helping to driving stronger volume across both the consumer and commercial channels in the fourth quarter.

However, looking ahead, IDC has predicted strong growth for Detachable tablets, and Ultraslim and Convertible Notebooks.

Commercial notebook shipments finished 2016 on a positive note, growing more than 2 percent year-over-year as more Windows 10 trials translated into real deployments. Meanwhile, consumer notebook shipments declined by only 1% from Q4 2015, helped by strong model launches in the Ultraslim and Convertible notebook categories.

In the tablet market, slate shipments continued their decline and detachables saw a dramatic decline in the fourth quarter – IDC puts this largely down to the segment's dependence on individual product launch cycles from the likes of Apple and Microsoft.

The absence of product refreshes in the quarter led to a year-over-year decline of 26.1% for detachables in Q4 2016 and contributed to a more tempered outlook for the entire tablet market. Despite the 2016 decline, IDC expects growth will return to the tablet market over the next five years due to the growing popularity of detachable devices.

Worldwide Mobile Device Tracker senior research analyst, Jitesh Ubrani says detachable tablets just aren't putting pressure on notebooks yet – regardless of what marketers says.

"Consumers are just starting to graduate from old, consumption-based, slate tablets to a more productive detachable tablet,” Ubrani says.

“At the same time, the benefits of having a thin, touch-sensitive, productivity-based machine is shining light on the traditional PC category, causing vendors and consumers to focus on more premium devices in the Convertible and Ultraslim space."

Looking ahead, while still negative, the outlook for traditional PCs has improved due to better economic conditions as well as slowing sales of competing devices such as tablets and smartphones.

Traditional PC shipments are expected to fall to 252 million units in 2021, representing a five-year CAGR of -0.6 percent, which is a slight improvement from the November forecast.

"As the tablet market works through the challenges of a maturing user base, the notebook ecosystem has seen success in assimilating a more mobile experience to the form factor while retaining its inherent superiority in the content creation arena, which remains critical for commercial buyers,” says Worldwide Personal Computing Device Tracker research manager, Jay Chou.

“Absent major external forces, IDC believes the notebook and traditional PC market overall will see relatively stable volumes with some growth in more mobile designs offset by declines in less mobile products.