have you got a NVIDIA chipset Video Card?
install the latest Drivers, do the proper modifications to XF86Config, select the correct Horizontal and Vertical Refresh of your monitor, change "nv" to "nvidia", set "(your resolution)/85Hz" and then restart X server...
Here is some peaks of my XF86Config, i have a PIII 750 Mhz with a Geforce2 MX and KDE has a Good Performance
PHP Code:
Section "Module"
# This loads the DBE extension module.
Load "dbe" # Double buffer extension
# This loads the miscellaneous extensions module, and disables
# initialisation of the XFree86-DGA extension within that module.
SubSection "extmod"
Option "omit xfree86-dga" # don't initialise the DGA extension
EndSubSection
# This loads the font modules
Load "type1"
Load "freetype"
Load "speedo"
# This loads the GLX module
Load "glx"
EndSection
PHP Code:
# Any number of monitor sections may be present
Section "Monitor"
Identifier "My Monitor"
# HorizSync is in kHz unless units are specified.
# HorizSync may be a comma separated list of discrete values, or a
# comma separated list of ranges of values.
# NOTE: THE VALUES HERE ARE EXAMPLES ONLY. REFER TO YOUR MONITOR'S
# USER MANUAL FOR THE CORRECT NUMBERS.
HorizSync 30-70
# HorizSync 30-64 # multisync
# HorizSync 31.5, 35.2 # multiple fixed sync frequencies
# HorizSync 15-25, 30-50 # multiple ranges of sync frequencies
# VertRefresh is in Hz unless units are specified.
# VertRefresh may be a comma separated list of discrete values, or a
# comma separated list of ranges of values.
# NOTE: THE VALUES HERE ARE EXAMPLES ONLY. REFER TO YOUR MONITOR'S
# USER MANUAL FOR THE CORRECT NUMBERS.
VertRefresh 50-160
vendorname "Samsung"
modelname "SyncMaster 710s"
ModeLine "1024x768/85Hz" 98.9 1024 1056 1216 1408 768 782 788 822 -HSync -VSync
EndSection
PHP Code:
# **********************************************************************
# Graphics device section
# **********************************************************************
# Any number of graphics device sections may be present
Section "Device"
Identifier "VESA Framebuffer"
Driver "nvidia"
#VideoRam 4096
# Insert Clocks lines here if appropriate
vendorname "NVidia"
boardname "GeForce2 MX DDR"
EndSection
PHP Code:
# Any number of screen sections may be present. Each describes
# the configuration of a single screen. A single specific screen section
# may be specified from the X server command line with the "-screen"
# option.
Section "Screen"
Identifier "Screen 1"
Device "VESA Framebuffer"
Monitor "My Monitor"
# If your card can handle it, a higher default color depth (like 24 or 32)
# is highly recommended.
# DefaultDepth 8
# DefaultDepth 16
DefaultDepth 24
# DefaultDepth 32
# "1024x768" is also a conservative usable default resolution. If you
# have a better monitor, feel free to try resolutions such as
# "1152x864", "1280x1024", "1600x1200", and "1800x1400" (or whatever your
# card/monitor can produce)
Subsection "Display"
Depth 8
Modes "1024x768/85Hz" "800x600" "640x480"
Virtual 0 0
EndSubsection
Subsection "Display"
Depth 16
Modes "1024x768/85Hz" "800x600" "640x480"
Virtual 0 0
EndSubsection
Subsection "Display"
Depth 24
Modes "1024x768/85Hz" "800x600" "640x480"
Virtual 0 0
EndSubsection
Subsection "Display"
Depth 32
Modes "1024x768/85Hz" "800x600" "640x480"
Virtual 0 0
EndSubsection
EndSection