I'm going to review Throttlestop software. It's a free utility that controls CPU multiplier limits, and in LGA775 CPU voltage settings from inside Windows.
Throttlestop was designed to extend battery life in laptop computers by limiting CPU speed, and voltage when full power wasn't needed. It also has extensive monitoring and some testing abilities. It works much like Speedstep, only it can set a lower limit on CPU multiplier than Intels maximum. Core 2 Extreme CPUs don't have a maximum multiplier (or it's very very high) so this program can increase the multiplier form it's base setting even if the BIOS doesn't support this.
Throttlestop features real time temperature readouts an all cores. GPU temperature readout. Voltage setting and actual voltage displays. It shows processor usage in %. It has a benchmark feature that rums a 30 second benchmark to test stability of a setting, and a 15 minute test for temperature monitoring. It saves maximum temperature reached so if you can't see TS in a game you can see what the CPU temperature rose to.
There is a slight learning curve , so I would advise getting the program and practicing with it some before overclocking. You need to open it twice before you can change settings. CPUZ is useful for showing the computer status when TS is not running. I've never seen the 2 programs disagree about what's going on. Remember to always raise voltage before changing a multiplier. Changes can only be made in whole multipliers on 65nm CPUs. The steps are large. On 45nm chips with a 333FSB 1/2 steps are provided. This program changes a multiplier when you select it, not when you hit "save". For best results I recommend doing any cooling mods first, such as heatsinking the VRM, and Chipset. Lapping the CPU and cooler. Plus any fan improvements needed.
The program behaves differently in XP than in Windows7.
In XP there is a display in the taskbar that you can set up with different colored readouts for CPU speed, temperature, and GPU temperature. In options you can set it up to save the VID, and Multiplier when you reboot, or let it return to default values. This can save you when trying extreme setting that might be unstable. The "C states" button turns Speedstep off and on. Again it can be helpful to reboot with Speedstep on if you are experimenting. Turning it off is good for validations without CPU loading. Just be sure you can reboot successfully. XP benchmarks faster than 7 in most programs.
In Windows7 the experience is a little different. Windows Security won't let it run automatically at startup. Microsoft won't give authorization to overclocking programs. Windows will let it be pinned to the taskbar, and wont ask for permission to run it if Windows security is set at it's lowest setting. I advise using a complete security suite if you run this setting. I also pin CPUZ there so when I turn on my computer I can check it's status without activating TS. This let's me run without the overclock when web browsing, but the O/C is just a click or 2 away when I want it. I open TS and the voltage goes up immediately, then I can turn off Speedstep if I want to be sure it's at full speed. If it isn't, cycling EIST off and on returns control to TS.
Updated 1/14/2016
There is a new Throttlestop 8.00 beta. It has support for 6-8 core CPUs. From what I've seen it controls voltage in newer CPUs than LGA775 which v.6.00 didn't before. It still requires an unlocked CPU to overclock.
Even if you don't have a locked BIOS, or Core2X CPU. You can run this program while testing with Prime 95 etc. to monitor each CPU core separately. This can let you know if you have a good or bad example of a CPU.
Throttlestop was designed to extend battery life in laptop computers by limiting CPU speed, and voltage when full power wasn't needed. It also has extensive monitoring and some testing abilities. It works much like Speedstep, only it can set a lower limit on CPU multiplier than Intels maximum. Core 2 Extreme CPUs don't have a maximum multiplier (or it's very very high) so this program can increase the multiplier form it's base setting even if the BIOS doesn't support this.
Throttlestop features real time temperature readouts an all cores. GPU temperature readout. Voltage setting and actual voltage displays. It shows processor usage in %. It has a benchmark feature that rums a 30 second benchmark to test stability of a setting, and a 15 minute test for temperature monitoring. It saves maximum temperature reached so if you can't see TS in a game you can see what the CPU temperature rose to.
There is a slight learning curve , so I would advise getting the program and practicing with it some before overclocking. You need to open it twice before you can change settings. CPUZ is useful for showing the computer status when TS is not running. I've never seen the 2 programs disagree about what's going on. Remember to always raise voltage before changing a multiplier. Changes can only be made in whole multipliers on 65nm CPUs. The steps are large. On 45nm chips with a 333FSB 1/2 steps are provided. This program changes a multiplier when you select it, not when you hit "save". For best results I recommend doing any cooling mods first, such as heatsinking the VRM, and Chipset. Lapping the CPU and cooler. Plus any fan improvements needed.
The program behaves differently in XP than in Windows7.
In XP there is a display in the taskbar that you can set up with different colored readouts for CPU speed, temperature, and GPU temperature. In options you can set it up to save the VID, and Multiplier when you reboot, or let it return to default values. This can save you when trying extreme setting that might be unstable. The "C states" button turns Speedstep off and on. Again it can be helpful to reboot with Speedstep on if you are experimenting. Turning it off is good for validations without CPU loading. Just be sure you can reboot successfully. XP benchmarks faster than 7 in most programs.
In Windows7 the experience is a little different. Windows Security won't let it run automatically at startup. Microsoft won't give authorization to overclocking programs. Windows will let it be pinned to the taskbar, and wont ask for permission to run it if Windows security is set at it's lowest setting. I advise using a complete security suite if you run this setting. I also pin CPUZ there so when I turn on my computer I can check it's status without activating TS. This let's me run without the overclock when web browsing, but the O/C is just a click or 2 away when I want it. I open TS and the voltage goes up immediately, then I can turn off Speedstep if I want to be sure it's at full speed. If it isn't, cycling EIST off and on returns control to TS.
Updated 1/14/2016
There is a new Throttlestop 8.00 beta. It has support for 6-8 core CPUs. From what I've seen it controls voltage in newer CPUs than LGA775 which v.6.00 didn't before. It still requires an unlocked CPU to overclock.
Even if you don't have a locked BIOS, or Core2X CPU. You can run this program while testing with Prime 95 etc. to monitor each CPU core separately. This can let you know if you have a good or bad example of a CPU.