What, do you run games at 1024x600? The first Dragon Age should have majorly strained your PC at any respectable resolution; it's worse than game consoles. Dragon Age II is much the same in DirectX 9, and even worse in DirectX 11 but you can't even try that. The Witcher 2...you didn't have a hope in hell of running The Witcher 2.
Most games are made to be playable on console, so the minimum requirements often remain the same. But devs often throw in high-res textures and better effects settings on the PC version, so if you want to stay on top you really do need to upgrade.
It was 1280X800 resolution. And my PC played Dragon Age and Dragon age 2 at playable frame rates. No major lag issues, except for a couple fights and even then it was playable.
My PC also ran Fallout New Vegas, on low settings and I had no lag or slow down issues with that game at all. Even the dam fight where 300 people were running around, no lag.
Specs:
Windows Vista home premium 32 bit OC SP2
Emachines model ET1161-07
Processor: AMD athlon dual core processor 4050e 2.1 GHZ.
Ram: 3gb DDR2
GPU: Geforce 7600 GS 512 MB (got this at best buy for like $120 when I bought my PC 3 years ago)
Did ok on most games up until Witcher 2. My PC ran Crysis better than Witcher 2, but Crysis was borderline unplayable frame rates when Witcher 2 was a frame rate slide show.
And by minimum settings on those games, I am talking everything that can be turned off for performance was turned off. And it still looked better than console graphics.