I have WiFi router set up. Both my phone and Windows PC connects to the same WiFi. So I tried ES File Explorer to copy shared folders from my Windows PC to my mobile. However transfer speed goes as high as 570 KB/s but not more than that. Since I configured my WiFi router to allow speed as high as 300 Mbps I am guessing why it cant hit the Mbps speeds. What can I do improve on my speed since I move movies worth in GBs and it takes almost an hour or more. Is it limited by the speed of the mobile and its internals?
Your phone seems to be a bit older as it runs Android 2.3 - therefore I assume it does not support any faster WLAN connection than 54MBit.
Hence the theoretical maximum would be 54MBit = 6.75 MByte/sec but only if you have just a router and a phone. With your PC in the network each device gets less than that.
Depending on the network protocol used you also lose a lot of speed. SMB/CIFS as used by Windows shares is very ineffective. Better use FTP protocol and suitable client for the best speed.
If that does not improve the performance I would suggest using an sd-card in and sd-card reader directly attached via USB 2.0 to your PC.
I have the same issue on Google Nexus 10. And I've recently find out that this happens only in ES File Explorer. I've downloaded movie using Google Chrome and the speed was 7 000 kbps, but the same file from the same site through ES Exp - < 500 kbps...