5. Data Center Systems

Projected 2017 Growth Over 2016: 0.3 percent

Projected 2017 Spending: $171 billion

Projected 2018 Spending: $173 billion (up 1.2 percent)

Gartner cites a "seismic shift" in the data center systems market, with cloud offerings taking the place of hardware as businesses have opted to look at such options as co-location and data center services as a way to control costs and take some of their focus off IT infrastructures.