The Lenovo B590 has a better Wi-Fi standard than most laptops that were released around the same time as it. This portable PC has an 802.11n WiFi standard, whereas most laptops that were released around the same time as it have an 802.11b WiFi standard. In addition, this Lenovo laptop has an 802.11g WiFi standard.
An 802.11n WiFi standard is in fact the best Wi-Fi standard amongst all similar spec laptops that have been available for a comparable time to the B590.
An 802.11a WiFi standard is the worst Wi-Fi standard amongst similar types of laptop.