Maxis has updated the system requirements for the Sims 2. For people without a T&L graphics card, a 2.0 Ghz processor is now the minimum (instead of the previously stated 1.5 Ghz). There's also an exact list of supported graphics cards. The fresh specification can be found on this page or below:

If you have a T&L capable video card with at least 32 MB of video RAM then you need at least:

• 600 MHz P3 processor or better
• 256 MB RAM if Windows XP, Windows ME, Windows 98 or Windows 2000
• At least 3.5 GB of hard drive space

If you have a non-T&L capable video card (such as Intel Extreme Graphics or Radeon 7xxx Series) then you need at least:

• 2.0 GHz processor or better
• 256 MB RAM if Windows XP, Windows ME, Windows 98, or Windows 2000
• At least 3.5 GB of hard drive space

Supported video cards (and the more video memory the better):

• ATI Radeon™ series (7000 or better)
  • 7000, 7200, 7500 (requires 2.0 GHz processor)
  • 8500, All-In-Wonder 8500
  • 9000, 9200, 9500, 9600, 9700, 9800
• Nvidia® Quadro™ series
  • Quadro, Quadro2, Quadro4
• Nvidia® Geforce series (GeForce2 and better)
  • GeForce2
  • GeForce3, 3 Ti
  • GeForce4, 4Ti, MX 420, 440
  • GeForce FX 5200, 5600, 5700, 5800, 5900, 5950
  • GeForce 6800
• Intel® Extreme Graphics (requires 2.0 GHz processor)
  • 82845, 82865