Help how to flash and choose a firmware for i8552

[maxx125]

i have samsung galaxy win (grand quattro) I-8552 but it's so slow and have many lags , so i want to flash the device with a fast and new firmware , but i'm a beginner at rooting or flashing my question is how to flash my phone safely , how to choose a good firmware , and from where i can download ...... plz help me

 

[mikedt]

I used to have one of these. All ROMs for this phone are based on 4.1.2, and are really just modified and hacked stock Samsung firmware. As for details and what's available, can you read Chinese?
http://m.romjd.com/device/samsung-i8552/new/all/1
Unfortunately most good information for this phone is in Chinese. It was a relatively slow device anyway. Have you tried just factory resetting it?