The main difference is the amount of system memory. Nokia’s Lumia 520 shipped with just 512MB of RAM, which was a slight problem early on for some apps and games that required 1GB of RAM. The latest Lumia 525 resolves that with 1GB of RAM onboard. With little changed on the inside and out, Nokia’s Lumia 525 looks like a minor revision on the world’s most popular Windows Phone. It will ship in black, white, orange, and yellow colors with the option to swap colors thanks to a removable shell.
Whereas the Lumia 520 has helped push Windows Phone sales in the US, Nokia isn’t launching the Lumia 525 initially in this region. Instead, it will launch in most countriesthroughout Africa, Asia Pacific, and the Middle East. Nokia hasn't supplied pricing or an exact release date for the Lumia 525. We've reached out to Nokia for more information, and we'll update you accordingly.
Update: Nokia says the Lumia 525 will be available in Singapore initially on December 14th for SGD249 ($199).