Wifi slow and delays with wifi power save on This is what i get at a device factory reset. Samsung galaxy S7562 . I have tested over 30 different devices with my access point and this doesnt occur - no problems. 
The other access point I have has better times and works with this android but gets disconnected after some time and it wont connect again. It will connected after a minute or so.

If i turn wifi  power save off from service mode then it works without any problem. Problem is visible at my app where small chunks of information are sent. When browsing although pings are the same there is just slower loading of page.However it seems that pings get low for 1 or 2 secs while loading a page but still slow.

When i turn power save off it works fine though.

Any idea for permament slution ? Even to turn power save off always
It looks like you've already come across one solution: turning off Wi-Fi power saving. That option puts the Wi-Fi chip into a low-power state sometimes. This reduces power use, but the trade-off is that next time you want to use Wi-Fi, you have to wait a fraction of a second for the chip to power on again.

This page from the official Android documentation explains about Wi-Fi power states. It's targeted at app developers, so they can optimize the usage pattern of their apps to save power. Even so, it's easy to follow, and might be interesting for other users to understand how Android tries to save power.