"When you're No. 4 or 5 in a market, when No. 1 sneezes, you get pneumonia. When you're No. 1, you control your destiny. The No. 4s keep merging; they have difficult times." -- former GE head Jack Welch

You've got to hand it to Jack Welch -- the man knew how to turn a phrase. And this is why it's so important for investors in the personal computer industry to know which companies are winning (and which companies are losing) in the race to sell PCs to the masses. Wherever we may be in the computers cycle in any given year, and no matter how bad things get, you'll be better off investing in the No. 1 PC maker than in an also-ran.

Fortunately, thanks to the tech wizards at Amazon.com (NASDAQ:AMZN), we now know which desktop computers (and with the click of a button, which laptop computers too) were the best selling PCs of 2017.

HP 8300 Elite Small Form Factor Desktop Computer

Hewlett-Packard's HP 8300 Elite Small Form Factor Desktop Computer boasts 500 GB of storage and an Integrated Intel HD Graphics chip. Image source: Amazon.com.

Who won in desktops

According to Amazon's "Best Sellers" list, there was one clear winner in desktop PCs last year: HP, Inc. (NYSE:HPQ). The company still best known as "Hewlett-Packard" sold five of the top 10 best-selling desktop PC models in 2017, including the No. 1 HP 8300 Elite Small Form Factor desktop, the HP 22-b016 All-in-One desktop, and the HP Pavilion Power 580-023w Gaming Tower (ranked No. 1, 4, and 6, respectively, in Amazon's stats).

Japan's Acer (a publicly traded company, but only in Japan) was close behind its rival. Two Acer Aspire desktops, one featuring the Intel (NASDAQ:INTC) i3 processor and one with an i5, took the No. 2 and No. 3 slots. Privately held MINIX, Cyberpower, and Dell all tied for third place, with one high-selling desktop PC apiece. (In Dell's case, this was the Dell OptiPlex, Intel Core 2 Duo).

All 10 of these 10 best-selling PCs were Windows machines. Among desktops, at least, Apple computers remain a niche product.

Who won in laptops

And what were laptop shoppers buying in 2017? Here the news is not as good for HP. The company's top-selling laptop -- an HP 14 Inch "Stream" with a Celeron processor and Windows 10 operating system -- ranked only No. 2 on Amazon's top 10 list. And only three of those top 10 notebooks were HP products.

Instead, Acer took top honors, winning four of the top 10 slots and also the No. 1 position. Acer's Aspire E 15-inch notebook was the top-selling laptop PC of 2017.

Samsung came in at No. 3 with a Chromebook running Google's operating system. And ASUS (again, publicly traded in Japan) rounded out the list with two top-10 sellers in the laptop PC category.

Interestingly, out of all these top 20 desktops and laptops combined, only one machine -- Acer's Predator Helios -- featured the powerful Intel i7 processor. Most of the other units maxed out at an i5, which suggests that shoppers were price conscious last year, and happy to settle for a less powerful chip in exchange for getting a more attractive price.

What it means to investors

What conclusions can investors draw from the above? With seven of the top 20 best selling PCs of 2017, drawn from both the desktop and laptop categories, HP remains a force to contend with. On Amazon at least, HP appears to be the clear winner and the No. 1 seller of PCs overall for 2017. This success is reflected in the company's financial statements, with data from S&P Global Market Intelligence showing that HP enjoyed 11% year over year sales gains from its "Personal Systems" (which includes PC sales) division through October. In contrast, Acer's sales were up only 2% through October, and ASUSTeK's PC sales (and profits) were down.

That said, Acer didn't fall that far behind HP in 2017, scoring six top sellers across the desktop and laptop lines. What's more, as the world moves inexorably toward laptops and away from desktops, Acer's leading position in laptop sales is something HP should worry about.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.