copy all the seta commands for the particular machine you have and put in your autoexec.cfg file in your q3ut4 directory... make sure you don't include header like "FAST MACHINE" or at least comment that out.
FAST MACHINE
seta cg_brassTime "2000"
seta cg_draw3dIcons "1"
seta cg_drawHands "1"
seta cg_drawTeamOverlay "1"
seta cg_gibs "1"
seta cg_marks "1"
seta cg_markTotaltime "10000"
seta cg_maxFragments "32"
seta cg_maxPrecip "128"
seta cg_sfxBrassTime "3000"
seta cg_sfxMuzzleFlash "1"
seat cg_sfxParticle "1"
seta cg_sfxParticleSmoke "1"
seta cg_sfxShowDamage "1"
seta cg_sfxSurfaceImpacts "1"
seta cg_sfxTeamBands "1"
seta cg_showBulletHits "1"
seta cg_visibleBleeding "5"
seta cg_shadows "1"
seta cg_simpleItems "0"
seta cg_maxFragments "32"
seta com_blood "1"
seta com_maxfps "125"
seta r_allowExtensions "1"
seta r_colorbits "32"
seta r_depthbits "24"
seta r_detailtextures "1"
seta r_dlightbacks "1"
seta r_drawSun "1"
seta r_dynamiclight "1"
seta r_ext_compress_textures "0"
seta r_ext_compressed_textures "0"
seta r_fastsky "0"
seta r_finish "0"
seta r_flares "1"
seta r_inGameVideo "1"
seta r_lodBias "-2"
seta r_lodCurveError "10000"
seta r_picmip "0"
seta r_roundImagesDown "0"
seta r_stencilbits "8"
seta r_subdivisions "1"
seta r_swapInterval "0"
seta r_texturebits "32"
seta r_vertexLight "0"
seta s_compression "0"
seta s_doppler "1"
seta s_khz "22"
seta s_loadas8bit "0"
seta s_mixahead "0.2"
seta s_musicvolume "0"
MEDIUM FAST MACHINE
seta cg_brassTime "0"
seta cg_draw3dIcons "1"
seta cg_drawHands "1"
seta cg_drawTeamOverlay "0"
seta cg_gibs "0"
seta cg_marks "1"
seta cg_markTotaltime "5000"
seta cg_maxFragments "16"
seta cg_maxPrecip "32"
seta cg_sfxBrassTime "1500"
seta cg_sfxMuzzleFlash "1"
seat cg_sfxParticle "1"
seta cg_sfxParticleSmoke "1"
seta cg_sfxShowDamage "1"
seta cg_sfxSurfaceImpacts "1"
seta cg_sfxTeamBands "1"
seta cg_showBulletHits "1"
seta cg_visibleBleeding "3"
seta cg_shadows "1"
seta cg_simpleItems "0"
seta cg_maxFragments "16"
seta com_blood "1"
seta com_maxfps "100"
seta r_allowExtensions "1"
seta r_colorbits "32"
seta r_depthbits "24"
seta r_detailtextures "1"
seta r_dlightbacks "1"
seta r_drawSun "0"
seta r_dynamiclight "0"
seta r_ext_compress_textures "1"
seta r_ext_compressed_textures "1"
seta r_fastsky "0"
seta r_finish "0"
seta r_flares "0"
seta r_inGameVideo "1"
seta r_lodBias "1"
seta r_lodCurveError "125"
seta r_picmip "1"
seta r_roundImagesDown "1"
seta r_stencilbits "8"
seta r_subdivisions "25"
seta r_swapInterval "0"
seta r_texturebits "32"
seta r_vertexLight "0"
seta s_compression "1"
seta s_doppler "1"
seta s_khz "22"
seta s_loadas8bit "1"
seta s_mixahead "0.2"
seta s_musicvolume "0"
MEDIUM SLOW MACHINE
seta cg_brassTime "0"
seta cg_draw3dIcons "0"
seta cg_drawHands "1"
seta cg_drawTeamOverlay "0"
seta cg_gibs "0"
seta cg_marks "0"
seta cg_markTotaltime "0"
seta cg_maxFragments "16"
seta cg_maxPrecip "16"
seta cg_sfxBrassTime "1000"
seta cg_sfxMuzzleFlash "1"
seat cg_sfxParticle "0"
seta cg_sfxParticleSmoke "0"
seta cg_sfxShowDamage "1"
seta cg_sfxSurfaceImpacts "0"
seta cg_sfxTeamBands "1"
seta cg_showBulletHits "1"
seta cg_visibleBleeding "2"
seta cg_shadows "1"
seta cg_simpleItems "0"
seta cg_maxFragments "16"
seta com_blood "0"
seta com_maxfps "76"
seta r_allowExtensions "1"
seta r_colorbits "32"
seta r_depthbits "16"
seta r_detailtextures "0"
seta r_dlightbacks "1"
seta r_drawSun "0"
seta r_dynamiclight "0"
seta r_ext_compress_textures "1"
seta r_ext_compressed_textures "1"
seta r_fastsky "0"
seta r_finish "0"
seta r_flares "0"
seta r_inGameVideo "0"
seta r_lodBias "1"
seta r_lodCurveError "125"
seta r_picmip "1"
seta r_roundImagesDown "2"
seta r_stencilbits "0"
seta r_subdivisions "90"
seta r_swapInterval "0"
seta r_texturebits "16"
seta r_vertexLight "0"
seta s_compression "1"
seta s_doppler "0"
seta s_khz "22"
seta s_loadas8bit "1"
seta s_mixahead "0.14"
seta s_musicvolume "0"
SLOW MACHINE
seta cg_brassTime "0"
seta cg_draw3dIcons "0"
seta cg_drawHands "0"
seta cg_drawTeamOverlay "0"
seta cg_gibs "0"
seta cg_marks "0"
seta cg_markTotaltime "0"
seta cg_maxFragments "0"
seta cg_maxPrecip "0"
seta cg_sfxBrassTime "0"
seta cg_sfxMuzzleFlash "0"
seat cg_sfxParticle "0"
seta cg_sfxParticleSmoke "0"
seta cg_sfxShowDamage "0"
seta cg_sfxSurfaceImpacts "0"
seta cg_sfxTeamBands "1"
seta cg_showBulletHits "0"
seta cg_visibleBleeding "0"
seta cg_shadows "0"
seta cg_simpleItems "1"
seta cg_maxFragments "0"
seta com_blood "0"
seta com_maxfps "76"
seta r_allowExtensions "1"
seta r_colorbits "16"
seta r_depthbits "16"
seta r_detailtextures "0"
seta r_dlightbacks "0"
seta r_drawSun "0"
seta r_dynamiclight "0"
seta r_ext_compress_textures "1"
seta r_ext_compressed_textures "1"
seta r_fastsky "0"
seta r_finish "0"
seta r_flares "0"
seta r_inGameVideo "0"
seta r_lodBias "2"
seta r_lodCurveError "125"
seta r_picmip "3"
seta r_roundImagesDown "2"
seta r_stencilbits "0"
seta r_subdivisions "90"
seta r_swapInterval "0"
seta r_texturebits "16"
seta r_vertexLight "1"
seta s_compression "1"
seta s_doppler "0"
seta s_khz "11"
seta s_loadas8bit "1"
seta s_mixahead "0.14"
seta s_musicvolume "0"