There are many factors involved in the actual throughput of your wireless connection (MIMO, WiFi standard, Encryption, Interference from other devices, etc). Since you are getting the same througput that you were getting with your older PC, it suggests that your other PC was already using the highest possible connection for your environment.
Ethernet connections (Wired LAN) normally have higher troughput since they have less network overhead and less environmental interference.
Just to mention a few factors:
- Speed of the connection with our ISP.
- Maintaining the dependable operation and security of a wireless Network reduces the product's raw speed by 30 or 50 percent.
- Environmental factors like barriers and interference from other Wi-Fi clients also affect wireless signals.
- The Intel® Dual Band Wireless-AC 3165 is a 802.11ac, dual band, 1x1 Wi-Fi + Bluetooth® adapter. However, if for example, your Wireless acces point is 802.11g, the connection will be limited by the router capabilities.
- The type of encryption also affects the data rate. WPA2 is the current standard. For more information, please check the following advisory: Wireless Networking — Data Rate Will Not Exceed 54 Mbps When WEP or TKIP Encryption is Configured
For additional details about this, you can check the following documents: