Maybe not. One user told me that with the latest Ralink driver there is no lag at all. He said:
'I would like to let you know that the latest Ralink rt73 drivers have a built-in solution for the lag spike problem. Since Vista version 22.214.171.124 and XP version 126.96.36.199 of the rt73 driver there is an option called "Smart Scan". If you enable that, the lag spike is gone.'
And if you have no wireless connection, WLAN Optimizer is useless for you anyway.