CS:S keine konstanten FPS

Hallo,
Ich hab ein Problem mit meinem CSS . Wenn ich z.B. auf de_dust2 spiele, fange ich mit 70-80 fps an und es sinkt langsam bis auf 20 fps (!!!) .
Meine Temperaturen während des zockens ->
Motherboard 45 °C (113 °F)
CPU 67 °C (153 °F)
Grafikprozessor (GPU) 57 °C (135 °F)
CPU 2722 RPM

Mein System/Hardware:->
Betriebssystem Microsoft Windows XP Home Edition
CPU Typ Intel Pentium 4 524, 3066 MHz (23 x 133)
Motherboard Name :Gigabyte GA-8S649MF (3 PCI, 1 PCI-E x16, 2 DDR DIMM, Audio, LAN)
Motherboard Chipsatz SiS 649
Arbeitsspeicher [ TRIAL VERSION ] -> 1024 mb ram
Grafikkarte GeForce 8500 GT (512 MB)
Monitor LG 702B [17" CRT] (1346134582)
Soundkarte Realtek ALC655 @ SiS 7012 Audio Device
Festplatte SAMSUNG HD160JJ (160 GB, 7200 RPM, SATA-II)
DMI Systemprodukt GA-8S649MF

CPU Takt 3066.8 MHz (Original: [ TRIAL VERSION ] MHz)
CPU Multiplikator 23.0x
CPU FSB 133.3 MHz (Original: 133 MHz)
Speicherbus 200.0 MHz
L1 Trace Cache 12K Instructions

GPU Codename G86GT (PCI Express x16 10DE / 0421, Rev A1)
GPU Takt (Geometric Domain) 500 MHz (Original: [ TRIAL VERSION ] MHz, overclock: 400%)
GPU Takt (Shader Domain) 1080 MHz (Original: [ TRIAL VERSION ] MHz)

CPU 2557 RPM

CPU Typ Intel Pentium 4 524, 3066 MHz (23 x 133)
CPU Bezeichnung Prescott
CPU stepping G1
CPU #0 Intel(R) Pentium(R) 4 CPU 3.06GHz, 3066 MHz
CPU #1 Intel(R) Pentium(R) 4 CPU 3.06GHz, 3066 MHz

Liegt es daran, dass mein PC zu warm wird ? Ich hab die Seitenverkleidung schon abgenommen und mein PC sollte eig genügend Luft bekommen bzw Kühlung. Aber wenn ich die GraKa anfasse, bekomme ich fast brandblasen .
Im Spiel hab ich die GraKaEinstellungen auf Niedrig/Minimum gemacht. Anti Aliasing, V-Synchr. sind alle aus oder auf minimum.
Hab ich ne Chance meinen PC noch zu pushn sodass ich konstant um die 55-60 fps rumdaddeln kann ?
P.S. Spiele nur auf Tickrate 100 server, falls das wichtig sein sollte.

Meine cfg: ->
cl_righthand "1"
cl_rumblescale "1.0"
cl_debugrumble "0"
cl_team "default"
cl_class "default"
cl_detail_max_sway "0"
cl_detail_avoid_radius "0"
cl_detail_avoid_force "0"
cl_detail_avoid_recover_speed "0"
cl_chatfilters "31"
cc_linger_time "1.0"
cc_predisplay_time "0.25"
cc_subtitles "0"
cc_lang ""
crosshair "1"
cl_observercrosshair "1"
cam_snapto "0"
cam_idealyaw "90"
cam_idealpitch "0"
cam_idealdist "64"
c_maxpitch "90"
c_minpitch "0"
c_maxyaw "135"
c_minyaw "-135"
c_maxdistance "200"
c_mindistance "30"
c_orthowidth "100"
c_orthoheight "100"
joy_name "joystick"
joy_forwardthreshold "0.15"
joy_sidethreshold "0.15"
joy_pitchthreshold "0.15"
joy_yawthreshold "0.15"
joy_forwardsensitivity "-1"
joy_sidesensitivity "1"
joy_pitchsensitivity "1"
joy_yawsensitivity "-1"
joy_response_move "1"
joy_response_look "0"
joy_lowend "1"
joy_lowmap "1"
joy_accelscale "0.6"
joy_autoaimdampenrange "0"
joy_autoaimdampen "0"
joy_diagonalpov "0"
joy_display_input "0"
joy_wingmanwarrior_turnhack "0"
lookspring "0"
lookstrafe "0"
joystick "0"
m_pitch "0.022"
m_filter "0"
sensitivity "1.8"
m_side "0.8"
m_yaw "0.022"
m_forward "1"
m_customaccel "0"
m_customaccel_scale "0.04"
m_customaccel_max "0"
m_customaccel_exponent "1"
m_mouseaccel1 "0"
m_mouseaccel2 "0"
m_mousespeed "1"
cl_mouselook "1"
cl_idealpitchscale "0.8"
net_graph "0"
net_scale "5"
net_graphpos "1"
net_graphsolid "1"
voice_modenable "1"
hud_fastswitch "1"
muzzleflash_light "1"
cl_buy_favorite_quiet "0"
cl_buy_favorite_nowarn "0"
cl_autowepswitch "1"
cl_autohelp "0"
cl_radartype "0"
cl_radaralpha "200"
cl_locationalpha "150"
cl_crosshaircolor "0"
cl_dynamiccrosshair "1"
cl_scalecrosshair "1"
cl_crosshairscale "0"
cl_crosshairalpha "200"
cl_crosshairusealpha "0"
cl_radar_locked "0"
overview_preferred_mode "1"
overview_preferred_view_size "600"
hud_classautokill "1"
overview_health "1"
overview_names "1"
overview_tracks "1"
overview_locked "1"
overview_alpha "1.0"
spec_scoreboard "0"
cl_spec_mode "1"
commentary_firstrun "0"
scene_showfaceto "0"
ai_report_task_timings_on_limit "0"
ai_think_limit_label "0"
npc_height_adjust "1"
sv_pvsskipanimation "1"
scene_showlook "0"
scene_showmoveto "0"
commentary "0"
xbox_throttlebias "100"
xbox_throttlespoof "200"
xbox_autothrottle "1"
func_break_max_pieces "15"
suitvolume "0.25"
sv_noclipaccelerate "5"
sv_noclipspeed "5"
sv_specaccelerate "5"
sv_specspeed "3"
sv_specnoclip "1"
sv_skyname "sky_urb01"
sv_backspeed "0.6"
joy_wingmanwarrior_centerhack "0"
joy_axisbutton_threshold "0.3"
voice_forcemicrecord "1"
voice_enable "1"
voice_scale "1"
snd_duckerthreshold "0.15"
snd_duckerreleasetime "2.5"
snd_duckerattacktime "0.5"
snd_ducktovolume "0.55"
adsp_debug "0"
snd_mixahead "0.1"
snd_musicvolume "1.0"
volume "1.0"
snd_pitchquality "1"
snd_digital_surround "0"
vprof_warningmsec "10"
vprof_unaccounted_limit "0.3"
vprof_verbose "1"
vprof_graphheight "256"
vprof_graphwidth "512"
texture_budget_background_alpha "128"
texture_budget_panel_bottom_of_history_fraction ".25"
texture_budget_panel_height "284"
texture_budget_panel_width "512"
texture_budget_panel_y "450"
texture_budget_panel_x "0"
budget_panel_height "384"
budget_panel_width "512"
budget_panel_y "50"
budget_panel_x "0"
budget_background_alpha "128"
budget_bargraph_range_ms "16.6666666667"
budget_panel_bottom_of_history_fraction ".25"
budget_history_range_ms "66.666666667"
budget_history_numsamplesvisible "100"
budget_show_history "1"
budget_show_averages "0"
budget_show_peaks "1"
budget_averages_window "30"
budget_peaks_window "30"
budget_bargraph_background_alpha "128"
r_gamma "0.5"
sv_forcepreload "0"
sv_voiceenable "1"
sv_logbans "0"
sv_log_onefile "0"
sv_logecho "1"
sv_logflush "0"
sv_logfile "1"
sv_logsdir "logs"
dsp_enhance_stereo "0"
dsp_volume "1.0"
dsp_slow_cpu "0"
cl_allowupload "1"
mp_decals "200"
r_drawmodelstatsoverlaymax "1.5"
r_drawmodelstatsoverlaymin "0.1"
r_ambientfactor "5"
r_ambientmin "0.3"
r_ambientboost "1"
r_eyesize "0"
r_eyeshift_z "0"
r_eyeshift_y "0"
r_eyeshift_x "0"
r_eyemove "1"
r_eyegloss "1"
r_3dsky "0"
skill "1"
closecaption "0"
con_enable "1"
cl_downloadfilter "all"
cl_allowdownload "1"
cl_forcepreload "0"
cl_soundfile "sound/player/jingle.wav"
cl_timeout "30"
cl_showpluginmessages "1"
tv_nochat "0"
sv_unlockedchapters "1"
cl_updaterate "20"
cl_cmdrate "30"
bgmvolume "1"

exec userconfig.cfg

Hab ich was vergessen ? Wenn ja, bitte bescheid geben

Danke im Vorraus
euer cuddy