The lag increase you mention may be possible, depending on the driver version you installed and the settings used in the router and the adapter. This may also be caused by external factors (interference, hardware issues, etc).
Please review and apply the following advisories as these actions may solve connectivity issues for Intel Wireless Adapters:
If you require further assistance, please provide the details of your system, such as PC model, Operating System version (including 32 or 64 bit), Wireless Adapter model and driver version shown in device manager, Intel® PROSet/wireless software version, router model and firmware version, distance to the router, etc.
Did you test the connection when you were using the MS Windows* drivers? if you did, what were the results?