3600m is based on 8800m GPU and FX5800 has the same GPU as GTX 280. They're in fact the same cards. Only difference between quadro and geforce is graphics card description in firmware so it would only take geforce or quadro drivers. Unless you nudge it a little to install quadro drivers.

I don't have cottage model, or forest ruin so I can't try it, but what are preview render setting in both cases? Cottage interior looks like it has different textures for floor and ceiling for gamer (or beter said regular) card case when compared to quadro, and wall texture is strectched across the wall, i.e. like wrong U and V scale settings in material room.

Here's my example. First is with default render preview settings, and second is with maxed settings.