Can low RAM and large OBB file size be an issue?

Here are the important details of my application :

APK size : 9mb

OBB size : 350mb

The game runs on all devices except :

Samsung Galaxy ace Plus

Google nexus S

-Both have 512 MB RAM

-Both have ARMv7 processors

The crash happens here:

WWW www = WWW.LoadFromCacheOrDownload(uri , 0);

//the return statement never executes

yield return www;

Any idea how low RAM could affect the game?

Note : Game is made in Unity 3D 4.2.0