On July 19, software giant Microsoft (NASDAQ:MSFT) is set to report earnings for the fourth and final quarter of its 2018 fiscal year. Last quarter, Microsoft delivered strong results. Revenue soared 16% to $26.8 billion, and diluted earnings per share popped 36%, reaching $0.95.

That performance wasn't driven by strength from just one of its business units -- every one of Microsoft's reporting segments grew by a double-digit percentage, and each of its product categories delivered positive growth as well.

Microsoft Surface devices.

Image source: Microsoft.

Great earnings results have become the norm for Microsoft, which has no doubt helped the stock continue to notch new all-time highs.

Here are a few things investors should be on the lookout for when the company reports this week.

1. The revenue story

One of the reasons that Microsoft's performance last quarter was notable is that the company managed to deliver 16% revenue growth off of an already enormous $23 billion-plus baseline. And in this latest report, momentum could build further with 18.2% year-over-year growth expected.

However, it's important to remember that while revenue growth should accelerate in the fourth quarter, the rate will likely moderate heading into fiscal year 2019 with analysts forecasting just over 10% growth for the upcoming year.

2. How's Surface doing?

Microsoft has spent years building out its Surface brand of computers. The product line began with two models -- Surface RT and Surface Pro. Since then, Microsoft has broadened that portfolio considerably, adding the Surface Book notebook as well as the Surface Studio all-in-one desktop to the lineup.

Most recently, Microsoft announced the Surface Go, which starts at $399. The previous entry-level Surface device, the Surface 3, was priced higher at $499. Meanwhile, Microsoft's other Surface products tend to be ultra-premium offerings that carry price tags to match, so we may be seeing a shift in Microsoft's strategy to evolve its Surface brand into a family of products that can compete at a broader set of price points. Such a strategy allows Microsoft to accelerate both unit shipments as well as Surface revenue growth (since Microsoft is, in effect, expanding its addressable market).

Last quarter, Microsoft reported that Surface revenue grew 32% year-over-year as it "continued to transition to the latest products in [its] portfolio" and saw "a prior year comparable impacted by product end-of-life-cycle dynamics."

Microsoft was bullish on this product category during its last earnings call, telling investors to expect "high teens" revenue growth as the company rolled out new products. Pay close attention to the revenue guidance that management provides for this product line -- that'll give investors insight into the sustainability of Surface's growth trajectory.

3. Windows OEM performance

Last quarter, Microsoft reported that its "Windows OEM" revenue -- that's revenue generated selling copies the Windows operating system to personal computer makers -- grew 4%. That growth was powered by "OEM Pro revenue growth of 11%."

For context, Microsoft's Windows operating system is dominant in both the consumer and commercial PC markets. And OEM Pro revenue growth was "in line with a strong commercial PC market," while demand for the latest Windows 10 operating system from enterprises was "healthy."

However, Microsoft did say that its non-Pro Windows OEM revenue declined by 8% last quarter and actually did worse than the overall personal computer market, "driven by a higher mix of lower-priced licenses and continued pressure in the entry-level price category."

Recently, market research companies IDC and Gartner said the personal computer market grew for the first time in years, with the latter stating that "PC shipment growth in the second quarter of 2018 was driven by demand in the business market, which was offset by declining shipments in the consumer segment."

Keep a close eye on Windows OEM revenue, including any commentary management might have on the sustainability of the trends it's seeing. Based on the industry reports, as well as PC chip giant Intel's recent guidance increase, I wouldn't be surprised to see a solid quarter for the Windows OEM business, with the strength once again coming from the OEM Pro side of things.