This message was posted on behalf of Intel Corporation
We understand you're experiencing low download speeds when connecting through your Intel® Centrino® Wireless-N 1000 in Windows* 8.1.
Please keep in mind that your wireless adapter has been discontinued and is no longer applicable for support. The latest driver for the Centrino® Wireless-N 1000 (for Windows* 8.1) is driver version 220.127.116.11, which is included in our PROSet/Wireless Software package version 18.40.4.
While it's possible that the performance issue may be a reflection of this model's lower end single band, 1x2 (1 transmit and 2 receive spatial streams) configuration. We can also recommend making sure that your router/access point is using the latest firmware, and that your adapter isn't being throttled through QoS (Quality of service, or priority list) settings.
NOTE: Any links provided for third party tools or sites are offered for your convenience and should not be viewed as an endorsement by Intel® of the content, products, or services offered there. We do not offer support for any third party tool mentioned here.
Another thing that can be checked is the actual connection rate between your adapter, and the router. When you measure download speeds, it only takes into account how long it takes to download a package from the internet, it does not account for all the unseen package overhead such as encryption and routing information. The Centrino® Wireless-N 1000 should be able to reach a receive rate of up to 300 Mbps (although 150 may be it's transmit rate limit).
To check for this, you will need to open a command prompt (right click the Windows* logo on your task bar, choose Command Prompt (admin) from the menu), and run the following command: netsh wlan show interfaces
We hope this information helps.