anyone tried that hack for via mobo users, espcially kt266 to kt400 people. some reported a lost of 5-10 degrees celsius on their cpu temp which sounds all pretty nice but anyone here at spcr tried it? just wanna get some opinions before i use it. it is supposed to enable the cpu halt command which is used by "cool and quiet" on amd 64 (i think).

http://www.ocmodshop.com/default.aspx?a=125%20

Yup - check the sticky thread at the top of this forum for a pretty comprehensive summary of options & references.

But in any event it is academic: to prove your PC is silent even when working you should join our Folding at Home team, here.

thankx for reply dukla! i'll be using the vcool software, hope it works well. but i have the 7vax kt400 which says in your link thats it is bios compatible.. i didnt see any options in my bios referring to this cooling thingy. anyways... ill probably get it working with vcool or , last resort, with the registry change.

The list is compiled form sources at xbitlabs. If your newest BIOS does not offer an option I will scratch it from the list.

Have anyone seen a working solution for VIA KT600?

The ASUS A7V600 I got is a quite new model, but I can't see any S2K Bus Disconnect support in BIOS.
I really don't like this motherboard, but on the other hand I got a good CPU. 2500+@222x11 : 1,65V, no problem even under Prime95.




No. Cool & quiet changes Vcore and multiplier, the newest version of the Athlon 64 can go down to 1000 MHz @ 1,1 V.

just tried Vcool on my kt400.. it didnt worked..
tried the manual hack register change..
all i can say is HOLY CRAP i lost 10 degrees celsius idle
went from 41 C to 30 C in a blistering second
i use the noisy coolermaster aero7+ at minimum speed
sory duk i wont be joining folding soon, well not until my computer is more silent
anyways my mobo was on xbitlabs list but didnt have the bios option
hey mats maybe you can just check if the register and data are the same... just checking shouldn't hurt but it seems to be no kt600 pcr files

Ok, I will write a comment in the list.

The KT400 files you can find on the web are working for the KT600. I tried it.

Yup - just zap register D5 in the northbridge. It is probably set to '1C' by the BIOS, you need to add the bit that changes '1C' to '1E'. WPCregEdit/Set will do this for you in Win, the links in the sticky also show how to do it in Linux.

Confirmed: It works on my ASUS A7V600.

INCREDIBLE!!!!!

I did it, and my temps went from 56(BIOS)/47(ASUS PC Probe) to 42/38!!

56? Yeah, I DO got bad caseflow... so this is very good for me! Imagine what will happen after some undervolting and better caseflow!

Thanks jojo4u and dukla2000 for your help!

dukla2000:
What about register D2, should I change that too like OCModShop did with reg 92 in KT400?

I dont bother - it never did anything for me. (Cant remember what the actual bit is even for.)

ps - just did a check and the notes I have say
[D2:7]=Disc when STPGNT# Detect 0=disable 1=enable
which all looks promising, except as I say I never noticed any difference so figured why fix it.

Mats - are those your idle temps? I thought this trick only brings your idle temps down but load stays the same, since every cycle draws energy.

[D2:7]=Disc when STPGNT# Detect 0=disable 1=enable -- What does that mean?



Yes it's in idle, since it's in BIOS!

The temp rised to 47 (PC Probe) when playing Beyond good and evill for a couple of hours. The temp changes very fast, both up and down. Now it's 38 again.
47 degrees used to be my MINIMUM, and now I only get it when I deserve it! GREAT!!!

Some temps (11x multiplier, Vcore = 1,65 V, idle, PC Probe):

1100 MHz, 38 degrees
1833 MHz, 38 degrees
2200 MHz, 40 degrees
2442 MHz, 44 degrees

I have thought about this and folding... what if one set F@H to run at 80-90% and use the remaining cycles for cooling the CPU (which with this hack should be very efficient), that way you can run the fan at a slower speed and don´t have to worry about overheating from F@H

The easy part is if the bit is 0 the feature is disabled, if the bit is 1 the feature is enabled.

The bit in question is the most significant bit (bit 7) at address D2.

Disc when STPGNT# Detect is short for disconnect when STPGNT is detected. I can't explain the #. STPGNT is a low power (Stop Grant) state the Athlon's can enter where they draw 5.9A instead of 37.6A (typical, in this case the example is XP2700). For Athlons to enter Stop Grant mode the system bus has to be disconnected.

Register D5 is enabling the HALT mode. D2 should enable Stop Grant for even lower power usage.

You can read more in the AMD Data Sheets and the 'How it works' tab for VCool.

WOOHOO! You stars! Idle temps gone from 49deg C to 39! With a Sempron 2400, AC Copper Silent 2 and Gigabyte 7VT600-P-RZ (VIA KT600) mb. Man am I so glad I found this site

had a few problems running the exe file from the link above (couldn't unzip to get the instdd.exe installer), but I found that the ones here worked a treat - D2 to E9 (69 prev) and D5 to 1E (1C prev). Stuck those into WPCRSET and jobs a good 'un

Down to 38deg C now

Congratulations! I guess this thread was almost forgotten, but people may still have use for it though.

Well there are much more convenient tools available today. Have a look at http://forums.silentpcreview.com/viewtopic.php?t=20903
Maybe I should persuade the mods to put it on sticky....

Yes, I've seen them but I just assumed that they would be running in the background for some reason....

Yeah but thats neglectable. WPCRSET failed to reset the registers after an S3 standby. Perhaps new tools are managing that. Haven't tested by myself.

I tried it on my A7V600-X, works miraculously!!! Dropped from around 39C-32C right now with my 1.92Ghz 2600+ Barton.