Why no different framerate on different resolution?

[Mr Deap]

Unlike the previous generation system that mostly run in 480I or 480P.

Since the render is like 4 times less harsh how come current games on the XBOX 360 & PlayStation 3 still cap the same framerate at 1080P, 1080I, 720P, 480P & 480i?

 

[sevanig]

I wondered that myself when playing Lair in 720P when its a 1080P native game... I guess it just needs to be optimized for each resolution?(time constraints?)

 

[kyleb]

Many games just use scaling to support different output resolutions, so the game is still rendered the same regardless of the output resolution. Though I belive most if not all PS3 games use lower resolution rendering for 480p/i, and some 360 games do that too. For instance, I played CoD2 on my 360 at 480p becuase that results in far less framerate drops than HD output resolutions. I also recall having to dissable 1080i on my PS3 to force the Full Auto 2 demo to run at 720p becuase it runs like crap at 1080i. I've never played Lair so I can't comment on that.

 

[Mintmaster]

I think part of the reason is that games are made so that they load the CPU and tailor vertex count to sort of match the pixel load. It's never a hard transition between being limited by pixel count, vertex count, or CPU load, but the transition is indeed there.

When a game is targetting 30fps and your CPU load doesn't change much in the game, you might as well load the CPU enough to occupy 30ms per frame, even if the benefits are marginal. Polygon count is something console devs like to push, so there a good chance of not only having significant portions of a typical scene's rendering to be limited by vertex load, but some parts that are pixel limited would switch over to being vertex limited before getting, say, a 4x speedup from running at a quarter the resolution.

 

[nintenho]

Many games just use scaling to support different output resolutions, so the game is still rendered the same regardless of the output resolution. Though I belive most if not all PS3 games use lower resolution rendering for 480p/i, and some 360 games do that too. For instance, I played CoD2 on my 360 at 480p becuase that results in far less framerate drops than HD output resolutions. I also recall having to dissable 1080i on my PS3 to force the Full Auto 2 demo to run at 720p becuase it runs like crap at 1080i. I've never played Lair so I can't comment on that.

yeah, a FEW games that have framerate problems don't render in HD if you set the system to an SD resolution. I know that even fewer games like NBA Street: Homecourt let you have the game rendered in 1080P if you select the system to output at that but the framerate drops from 60 to 30 and I think there's less AA too.