attaching system info.  Whenever/whatever I attempt to change re: memory timings, system keeps rebooting.  Also, can't get Performance Mode to show active......

Thanks!  Any ideas appreciated...

CPU-Z Report
CPU-Z version 1.26.

CPU(s)      
Number of CPUs      2 (1 Physical)
CPU#1      APIC ID = 0
CPU Name      Intel Pentium 4
Name      Intel Pentium 4
Code Name      Northwood
Specification      Intel(R) Pentium(R) 4 CPU 2.40GHz
Family / Model / Stepping      F 2 9
Extended Family / Model      0 0
Brand ID      9
Package      mPGA-478
Core Stepping      D1
Technology      0.13 µ
Supported Instructions Sets      MMX, SSE, SSE2
CPU Clock Speed      3123.9 MHz
Clock multiplier      x 12.0
Front Side Bus Frequency      260.3 MHz
Bus Speed      1041.3 MHz
L1 Data Cache      8 KBytes, 4-way set associative, 64 Bytes line size
L1 Trace Cache      12 Kµops, 8-way set associative
L2 Cache      512 KBytes, 8-way set associative, 64 Bytes line size
L2 Speed      3123.9 MHz (Full)
L2 Location      On Chip
L2 Data Prefetch Logic      yes
L2 Bus Width      256 bits
CPU#2      APIC ID = 1
CPU Name      Intel Pentium 4 (logical unit)

Mainboard and chipset      
Motherboard manufacturer      ASUSTeK Computer Inc.
Motherboard model      P4P800SE, Rev 2.xx
BIOS vendor      American Megatrends Inc.
BIOS revision      080009
BIOS release date      10/01/2004
Chipset      Intel i865P/PE/G/i848P rev. A2
Southbridge      Intel 82801EB (ICH5) rev. 2
Sensor chip      Winbond W83627THF
FSB Select      800 MHz
Performance Mode      disabled
Graphic Interface      AGP
AGP Status      enabled, rev. 3.0
AGP Data Transfert Rate      4x
AGP Max Rate      4x
AGP Side Band Addressing      supported, enabled
AGP Aperture Size      128 MBytes

Memory      
DRAM Type      DDR-SDRAM
DRAM Size      1024 MBytes
DRAM Frequency      173.6 MHz
FSB:DRAM      3:2
CAS# Latency      2.5 clocks
RAS# to CAS#      4 clocks
RAS# Precharge      4 clocks
Cycle Time (TRAS)      8 clocks
# of memory modules      2
Module 0      Corsair DDR-SDRAM PC2700 - 512 MBytes
Module 1      Corsair DDR-SDRAM PC2700 - 512 MBytes

Software      
Windows version      Microsoft Windows XP Professional Service Pack 2 (Build 2600)
DirectX version      9.0c

Corsair DDR-SDRAM PC2700 - 512 MBytes