strange, I have no any mentioned issues running genuine game here. perhaps its specifics to yours hacked/modded version ? where I can get it ?
try to uncheck "Enable Translucent Join" in video settings, usually this speed optimization is harmless, but in some games it causes flickering of texts/etc, you have to disable it for such games.
or you may disable it at all if you have Nvidia GPU, this optimization mainly for ATI/AMD, which works slow in some cases.
in general - new renderer is MUCH faster in games which is extensively uses shadows, like Jet Set Radio for example. it is much faster in 2D games like Atomiswave MetalSlug6 or SamuraiShodown6. it supports all kind of framebuffer effects like Sega Extreme Sports sun effects of Vigilante 8 title screen. it have many other bugfixes or improvements made during last several years.