PC requirements

The Sims 3: Showtime System Requirements

The Sims 3: Showtime needs at least 2.0 GHz P4 processor or equivalent for XP/2.4 GHz P4 processor or equivalent for Vista and Windows 7 and At least 1 GB for XP / 1.5 GB for Vista and Windows 7 / at least 2 GB For NVIDIA ION™ computers of RAM.

Verified Sources: Steam store listing
The Sims 3: Showtime minimum and recommended PC specifications
Component Minimum
Operating system Windows XP (SP2), Windows Vista (SP1), or Windows 7
Processor 2.0 GHz P4 processor or equivalent for XP/2.4 GHz P4 processor or equivalent for Vista and Windows 7
Memory At least 1 GB for XP / 1.5 GB for Vista and Windows 7 / at least 2 GB For NVIDIA ION™ computers
Storage At least 1.5 GB of free space (7 GB if installing with The Sims 3) with at least 1 GB additional space for custom content and sa
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Other platforms

The Sims 3: Showtime is also available on these systems, where hardware is fixed and no per-PC check is needed:

Quick answers

Running The Sims 3: Showtime on PC

Can my PC run The Sims 3: Showtime?
Compare your CPU, GPU and RAM against the minimum column below. If your parts match or beat every minimum row, the game will launch — though you may need to lower settings. Matching the recommended column is what gets you 60fps at 1080p.
How much storage does The Sims 3: Showtime need?
At least 1.5 GB of free space (7 GB if installing with The Sims 3) with at least 1 GB additional space for custom content and sa