A standard Xbox 360 ISO for The Sims 3 should be approximately 6.8 GB to 7.3 GB . If the file is only a few megabytes, it is likely a virus.
Note: The Sims 3 is known to be relatively stable on Xenia, though you may need a decent GPU to maintain a smooth frame rate. On a Modded Xbox 360
The Sims 3 on Xbox 360 is a unique piece of gaming history, offering a more "game-ified" experience than its PC counterpart. Whether you're setting up a nostalgia trip on an emulator or keeping your physical console alive, having a backup ISO ensures your Sims will keep living their best (or most chaotic) lives for years to come.
Users with RGH (Reset Glitch Hack) or JTAG modified consoles use ISOs or "Games on Demand" (GoD) formats to play games directly from a hard drive without needing the disc.