Hi, i was seeing with umbra, performance will grow up very well, is still good to take care of the optimizations like : Joint or mix meshes, less draw distance, low res textures or lightmaps (let´s say, for a lower end videocard like 8500 GT…
Yes. There is no magic bullet for optimisation, you will generally need to combine multiple techniques and clever compromises to get the best performance out of your game.
Especially with something like occlusion culling, certain scenes might see a huge improvement, while others might gain little to no benefit. It’s not going to suddenly replace the need for batched drawcalls and limiting geometry.
Thanks for answering.
,… i think you´re right, i saw GTA 4 uses umbra, yet low frame rate in a geforce 9600 gt card, i guess the lack of optimization…
Mixing up meshes into one could be a problem too if I´m using mesh collider, maybe this correct?..
games performing bad are on desktops nearly always caused by users not having the appropriate settings for their machines, unhappily (thats the benefit of a platform like iphone that updates once per year only and otherwise is fixed and well known)
For a low end card like a 9600, medium settings without AA, potentially a bit higher depending on the resolution are the highest of feelings one can expect in a game like GTA4 
haha, yes that´s right, 9600 gt looks like a bit old, maybe that…