The HP ZBook 15 has a better Wi-Fi standard than most medium processor core laptops that came out more than two years ago. This laptop has an 802.11a WiFi standard, whereas most similar spec portable PCs that have been available for around the same time as it have an 802.11n WiFi standard. This notebook PC also have 802.11ac and 802.11b and 802.11g WiFi standards.
An 802.11a WiFi standard is in fact the worst Wi-Fi standard across all medium processor core laptops that have been around for around the same time as the ZBook 15.
Across similar types of notebook PC the best Wi-Fi standard is 802.11n.