802.11ac (Wi-Fi 5) NIC drivers for Windows XP is challenging because 802.11ac was standardized in 2013, near the end of life for Windows XP. While the OS does not natively support this standard, certain hardware manufacturers released specific drivers for their chipsets to maintain compatibility with legacy systems. Compatible 802.11ac Hardware and Drivers
The golden rule of legacy computing applies here: Let your 802.11ac NIC run on a modern OS where it belongs, and let your Windows XP machine rest on the reliable, stable 802.11n that it was designed to love.