To paraphrase Mark Twain, reports of the death of the PC market have been greatly exaggerated. Although Gartner expects worldwide PC shipments to slip 2.4% annually this year, it believes shipments will bounce back 3.7% next year thanks to the arrival of Windows 10 and next-generation processors.

Source: Pixabay.

Although single-digit growth doesn't sound exciting, investors should recognize the key players, trends, and pockets of growth within this market.

Hewlett-Packard (NYSE:HPQ) was once the largest PC manufacturer in the world. But over the past decade, the company has made some huge mistakes.

Between 2010 and 2011, HP switched CEOs twice. In 2010, CEO Mark Hurd resigned amid charges of sexual harassment. His successor, Leo Apotheker, then took HP on a roller-coaster ride by proposing that the company dump its core PC business. Apotheker also oversaw the acquisition of U.K. big data company Autonomy for $11 billion, which resulted in a disastrous $8.8 billion writedown for HP due to Autonomy's "inflated" contracts. Apotheker was subsequently fired and replaced by former eBay CEO Meg Whitman.

While HP inexplicably spun in circles, Lenovo (NASDAQOTH:LNVGY) gained ground in mobile by launching Android devices and introducing convertible laptops that could be folded back into tablets. Those devices proved popular, and by 2013, Lenovo toppled HP as the world's top PC manufacturer.

On the bright side, Whitman stabilized HP's growth. During the first quarter of 2015, HP and Lenovo respectively posted 3.3% and 3.4% annual growth in global PC shipments. The growth was fueled by decent demand for low-end Windows PCs like the $200 HP Stream 11 and pricier convertible devices like the Spectre x360. Unfortunately, selling cheaper devices also brings in less money -- last quarter, HP's revenue fell 6.8% annually as its net earnings dropped 20.6%.

HP channels Lenovo with the Spectre x360. Source: HP.

Most people think of iPhones and iPads when they think of Apple (NASDAQ:AAPL), but the tech giant is also one of the largest PC manufacturers in the world. Unlike many Windows PC makers, which are racing to the bottom of the market with cheap devices, Apple sells premium laptops and desktops. It's also the only maker of OS X devices, which shields its devices from hardware competitors.

Apple's new MacBook. Source: Apple.

According to Gartner, Apple's Mac shipments rose 19% year over year in the fourth quarter of 2014, which helped it claimed 7% of the global market and become the fifth largest PC maker in the world. Apple's annual growth in shipments also outpaced the top four PC makers in the world -- Lenovo, HP, Dell, and Acer. Apple dropped out of the top five PC makers worldwide during the first quarter, but it remains the third largest PC maker in the U.S., after HP and Dell, with a 12% market share.

Last quarter, Apple's Mac sales accounted for nearly 10% of the company's top line. That might not seem like much, but continued growth of Mac sales could reduce Apple's dependence on the iPhone, which accounted for almost 70% of its sales.

Intel and NVIDIA
All PCs require CPUs and GPUs. Therefore, investors should keep an eye on the respective market leaders in both categories: Intel (NASDAQ:INTC) and NVIDIA (NASDAQ:NVDA).

Intel's CPUs power over 90% and 80% of laptops and desktops worldwide, according to IDC. Its Xeon processors also have a near-monopoly of the data center market. Last year, revenue at Intel's PC and Data Center businesses, which together accounted for 88% of its revenue, respectively climbed 4% and 18% annually. Intel has deep pockets and its own foundry business, which enable it to launch smaller and more power-efficient designs more rapidly than "fabless" rivals.

Intel is also the market leader in GPUs thanks to its integrated graphics chipsets. However, NVIDIA firmly controls the market for add-in graphics boards (AIBs) for high-end graphics applications and gaming. Between the first quarters of 2014 and 2015, NVIDIA's market share in AIBs rose from 64.9% to 77.5%, according to research company JPR.

Nvidia's high-end GTX 960. Source: NVIDIA.

The bottom line
HP, Apple, Intel, and NVIDIA represent four different parts of the PC market that investors should watch closely. The battle between HP and its Windows rivals could substantially lower price expectations for laptops, while Apple remains protected by the barriers of brand appeal and a closed ecosystem. Meanwhile, Intel and NVIDIA manufacture essential hardware for PCs, which ties their fate to the future growth of the PC market.