Why?
Go browse around with the CVars.
By default, even on extreme settings, both POM (parallax occulsion mapping) and Texture Streaming are forced to off (0).
Now I'm barely running this game on Extreme and 30 FPS on a GT 240 GDDR5 so enabling them would kill my frame rate but would someone else try enabling them to see if it makes any difference?
It's r_usePOM for parallax occlusion mapping and for texture streaming:
e_TerrainTextureStreamingPoolItemsNum
e_VoxTerInGameTextureStreaming
g_hitDeathReactions_streaming
r_TexturesStreaming
r_TexturesStreamingMaxRequestedJobs
r_TexturesStreamingMaxRequestedMB
r_TexturesStreamingResidencyEnabled
r_TexturesStreamingResidencyThrottle
r_TextureLodDistanceRatio=
s_FileAccess
sys_budget_streamingthroughput
sys_budget_numdrawcalls
sys_budget_soundchannels
sys_budget_sysmem
sys_budget_videomem
Anyone want to give it a shot?