visual lagging (meter and playback header)

i've a macbookpro 13" 4Gb ram,i5 2,3 ghz,Reaper dont know why reaper's graphics (meters and playback header) lag too much, don't have any plugin,it always lag

Perhaps try different settings in Preferences > Appearance > UI Updates. "Fast always" may be what you want. By default, it is set to 'lazy' UI updating (for good reasons, imho).

ok,i've solved,it was "meter update frequency" option :D Thank you