Games Playable on GeForce 9500 GT / 1.5 GB DDR2 / Pentium 4 3.2 GHz (2008–2010 Budget Rig)

That's a ~2008–2010 budget rig. You'll run pre-2010 titles at Low/Medium 720p and many indie games. Modern AAA is impossible.

Playable Classics (2000–2010)

• Shooters: Half-Life 2, Portal, Team Fortress 2, Call of Duty 4: Modern Warfare, BioShock, F.E.A.R., Quake 4, Prey (2006).
• RPGs: Mass Effect 1, Oblivion, Fallout 3 / New Vegas (Low, ini tweaks), KOTOR 1/2, Vampire: The Masquerade – Bloodlines.
• Open World: GTA: San Andreas, GTA IV (Very Low, ~30fps), Just Cause 2 (Low).
• Strategy: StarCraft II (Low), Dawn of War 2, Civ IV/V (small maps), Total War: Medieval 2 / Empire.
• Horror/Action: Dead Space 1, Resident Evil 4/5, Batman: Arkham Asylum (Low).

Indie / Lightweight (Run Great)

• Stardew Valley, Terraria, Minecraft (Java + OptiFine), Celeste, Hollow Knight, Undertale, Hotline Miami, FTL, Papers, Please, Shovel Knight.

Optimization Tips

• Install OS + games on SSD (even SATA) — huge load-time win.
• Upgrade to 4 GB RAM if board supports (DDR2-800 2×2GB ~$15 used).
• Disable Aero / compositing (Win7 Basic theme).
• Set GPU to "Prefer Maximum Performance" in NVIDIA Control Panel.
• Config tweaks: Fallout / GTA IV ini edits for memory/threads.

Emulation

PCSX2 (PS2), Dolphin (GC/Wii), RPCS3 (light PS3), PPSSPP, Citra (3DS) — all run well on this CPU/GPU.

Upgrade path: Core 2 Quad Q9650 + GT 1030 / RX 550 = 1080p Low/Med modern indie/AA.