This is a much smaller file (approx 200MB) and is objectively a "better" download for your bandwidth.

Many users struggle with the Siemens download process because it is gated by a or login wall. Here is how to make that process better.

To ensure PLCSIM V15.1 runs smoothly without lag, your programming device should meet or exceed these specifications: SIMATIC STEP 7 and WinCC V15.1 TRIAL Download - Support

However, I can guide you on the legitimate ways to obtain this software and what "V15.1" entails.

Telemetry & feedback (privacy-respecting)

: Significant improvements in sequence performance and motion control resource support.