Software CPU cooling recomendations

Does anyone know of a decent CPU cooling program thats completley FREE? I've been using CPUIdle but i dont think its worth paying for it (all it does is send HLT commands for heavens sake...) . Its a shame Rain doesnt work on XP (AFAIK...)

But anyway, im using an Athlon XP 3000+, running Windows XP.

 

I thought that is all any of them did.

The NT? 2K/XP/2K3 OSes have built in cooling software, but once again, is only sending HLT commands to the CPU when it is idle. Pretty sure thats all the System Idle Process does.

 

to my knowledge the system idle process does not send hlt command to the CPU, it's simply there to make coding a bit easier, giving the CPU something to look at when it's not busy.
look here
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q263201&ID=Q263201
about 3/4 of the way down the page.

"System Idle Process - You cannot end this process from Task Manager.
This process is a single thread running on each processor, which has the sole task of accounting for processor time when the system isn't processing other threads. In Task Manager, expect this process to account for the majority of processor time."

 

Well while using CPU idle i did notice temps going down by the promised ammount so the OS ones cant be all that efficient.

 

Hmm, I guess I am wrong about what passes the command, but I do know that these OSes have this feature built in.

http://www.tech-report.com/reviews/2002q4/pentium4-3.06/index.x?pg=2

 

BTW, I may not be wrong.



Look at this.

http://lists.isb.sdnpk.org/pipermail/comp-list/2002-September/001342.html

http://www.techsupportforum.com/computer/topic/8098-1.html

 

perhaps I spoke too curtly. I will elaborate.

The HLT command that the system idle process isn't too terribly effective with AMD CPU's. It will stop the CPU from doing anything, but it won't put it into low power mode. In order to do this then the CPU actually neds to temporarily disconnect itself from the northbridge. it's an odd process, I'll try to explain it. Basically the athlon/duron processor when sent an HLT command simply stops doing work. the PLL still runs, awaiting a signal to wake up the CPU, it doesn't actually power down the CPU, think of it as a suspended state, not doing anything, but powered up and ready to go back to work instantly. in order to get the CPU to completely power down then you have to have the northbride disconnect it from the bus. This then signals the PLL to shut down the CPU, this is more of a hibernate state. until the northbridge turns the bus back on then the CPU doesn't draw power. I'll try to find a site that explains it better. I'm horrible with trying to explain white paper documents.

 

ok, so it seems that you can get the HLT command in the system idle process to work, but you have to make sure that ACPI idle is enabled in the bios.

 

this site works sometimes, sometimes not, but it explains the whole things.
http://vcool.occludo.net/VC_Theory.html&e=747

apparently from the vcool site.
The Athlon (or Duron) enters a lower power state only when its system bus is disconnected. However the (VIA-)Northbridge will only disconnect the bus if its "Bus Disconnect Enable" bit is set and the CPU is in STPGNT state.
VCool allows you to enable this bit so your CPU can relax when there's nothing to do.
Apparently some OSs and cooling utilities fall short in one or the other category:
Usually the OS has an idle loop and probably uses the ACPI register to put the CPU into STPGNT state but it forgets to set the Bus Disconnect Bit.
This is where a lot of (BIOS-)hacks and tools come into play: They set this infamous Northbridge bit - however if OS doesn't use the APCI register or the tool has it's own idle loop with just the HLT instruction, the CPU just won't cool off.

 

Aha!

So you do admit the System Idel Process sends HLT commands!



I gotta give you a hard time on that one

 

So I guess the next question is, are the XP HLT commands ineffective only with VIA chipsets? What about Nvidia?

Maybe I misunderstood.
This is good info, btw, thanks.

 

Hmm, that little program doesnt work, ive got a NVidia nForce2 Ultra 400 chipset which it doesnt support

 

well, I would have to say that since goldy saw a decrease in CPU temps using cpucool then XP's HLT command must not work on nvidia's chipsets either.