Hello
Do you notice this behavior only with Eco Mode setting or also with high performance power plan? This would mean you should set
Maximum Performance power option for WLAN card in power plan setting.
Beside WLAN driver update you should also check the BIOS version. Have a look on Toshiba page if there is a newer version and if yes try updating it:
http://eu.computers.toshiba-europe.com > Support & Downloads > Download Drivers
Check this!!!