Intel Wireless AC-8265 5GHz Gigabit speed issue

[ekanto]

Hello, 

I am using the AC-8265 wireless card that came with my laptop HP Probook 450 G5. I do also have a Realtek PCIe GbE Family Controller for ethernet and from that, I get almost up to 600-700Mb/s as my ISP support that much speed. But the issue is with WLAN. I am using the ASUS Dual-Band AC-1200 which supports up to 860Mb/s transfer rate. When I am on the 5GHz band, the adapter controller shows that my wireless link speed is 866Mb/s (Screenshot is given below) but the actual speed I get less than 100Mb/s. Or I can say in short, 5GHz  bandwidth is capped to 100Mb/s(Screenshot is given below). My question is, isn't the wireless adapted supposed to provide me speed more than 100Mb/s (), As my router and ISP both support the speed), and if yes, where is the problem? 

Thank you