I just got my new 5870, pretty happy with it so far, but in Oblivion I seem to be having problems.
I can't enable HDR or Bloom lighting, or shadows on grass/shadows from trees. I went to RenderInfo.txt in the Oblivion.ini section, here's what it said:
Renderer Device Information:
ATI Radeon HD 5800 Series
atklumdisp.dll
RenderPath : BSSM_SV_2_0
PSversion : 300
VSversion : 300
VStarget : vs_2_0
PStarget : ps_2_0
PS2xtarget : ps_2_0
maxPS20inst : 512
3.0 Shaders : no
Image space effects : yes
Nonpowerof2textures : yes
FP16ARGB blending : yes
FP16ARGB filtering : yes
High dynamic range : no
Bloom lighting : no
Refraction : yes
2.0 hair : yes
SLI mode : no
Water shader : yes
Water reflections : no
Water displacement : no
Water high res : no
Multisample Type : 0
Shader Package : 2
It seems to me that Some things on there are wrong, like I'm pretty sure the shader package on the 5870 is 3, and that it does support 3.0 shaders.
Well if anyone knows the answer much appreciated.