moniter shuts off randomly with games

i have recently installed ubuntu 8.10 on my Pentium4(single core) desktop with a Radeon 9700 Pro agp card 2gig ram. i have installed all available updates. i am not very experienced with linux, so please bare with me.

the issue comes up usually, but not always, during the startup of a game(native linux and windows via wine). i see no verbose signs of error, my monitor simply turns off. the only resolution when this happens is to restart the computer and pray nothing got corrupted.

different things can cause this, but i need help narrowing down whether it is a driver issue, overheating issue, or a voltage issue. one big thing that caught my eye was this
Max Speed: 1500 MHz;Current Speed: 2666 MHz
is that accurate? i know my processor can be overclocked very easily in the bios, but i dont actually know the true speed of the processor. just days ago, on this very computer under windows, i had just finished running a program that just sat in the background with priority set to low while it did a database building project for me ensuring that processor usage stayed at a steady 100% utilization for 6 days strait with no such error. along with that i played the same warcraft 3 then as i do now albeit with wine. (warcraft 3 is a ton faster on linux with wine then it was on windows and you even get bnet)

i dont know very many commands to pull system information, so if you know one that would provide more useful information please share.

(sudo dmidecode -t Processor)
Processor Information
 Socket Designation: Socket 478
 Type: Central Processor
 Family: Pentium 4
 Manufacturer: Intel
 ID: 27 0F 00 00 FF FB EB BF
 Signature: Type 0, Family 15, Model 2, Stepping 7
 Flags:
  FPU (Floating-point unit on-chip)
  VME (Virtual mode extension)
  DE (Debugging extension)
  PSE (Page size extension)
  TSC (Time stamp counter)
  MSR (Model specific registers)
  PAE (Physical address extension)
  MCE (Machine check exception)
  CX8 (CMPXCHG8 instruction supported)
  APIC (On-chip APIC hardware supported)
  SEP (Fast system call)
  MTRR (Memory type range registers)
  PGE (Page global enable)
  MCA (Machine check architecture)
  CMOV (Conditional move instruction supported)
  PAT (Page attribute table)
  PSE-36 (36-bit page size extension)
  CLFSH (CLFLUSH instruction supported)
  DS (Debug store)
  ACPI (ACPI supported)
  MMX (MMX technology supported)
  FXSR (Fast floating-point save and restore)
  SSE (Streaming SIMD extensions)
  SSE2 (Streaming SIMD extensions 2)
  SS (Self-snoop)
  HTT (Hyper-threading technology)
  TM (Thermal monitor supported)
  PBE (Pending break enabled)
 Version: Intel Pentium(R) 4
 Voltage: 0.0 V
 External Clock: 133 MHz
 Max Speed: 1500 MHz
 Current Speed: 2666 MHz
 Status: Populated, Enabled
 Upgrade: ZIF Socket
 L1 Cache Handle: 0x000A
 L2 Cache Handle: 0x000B
 L3 Cache Handle: No L3 Cache

(sudo lspci -v)
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon R300 ND [Radeon 9700 Pro]
 Subsystem: ATI Technologies Inc Device 0002
 Flags: bus master, stepping, 66MHz, medium devsel, latency 32, IRQ 12
 Memory at d0000000 (32-bit, prefetchable) [size=128M]
 I/O ports at 9000 [size=256]
 Memory at e5000000 (32-bit, non-prefetchable) [size=64K]
 [virtual] Expansion ROM at e4000000 [disabled] [size=128K]
 Capabilities: [58] AGP version 2.0
 Capabilities: [50] Power Management version 2
 Kernel modules: radeonfb

01:00.1 Display controller: ATI Technologies Inc Radeon R300 [Radeon 9700 Pro] (Secondary)
 Subsystem: ATI Technologies Inc Device 0003
 Flags: stepping, 66MHz, medium devsel
 Memory at d8000000 (32-bit, prefetchable) [disabled] [size=128M]
 Memory at e5010000 (32-bit, non-prefetchable) [disabled] [size=64K]
 Capabilities: [50] Power Management version 2