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 Post subject: Custom A64 Undervolting
PostPosted: Fri May 28, 2004 9:11 pm 
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Joined: Fri May 21, 2004 10:49 am
Posts: 40
I have an Athlon64 3200+ running on a K8V deluxe. I've had my share of troubles with the system but I picked it because the board is passively cooled. Anyway, I've been lurking here for quite some time and wanted to share some of my experience. Thanks for all the wonderful posts and reviews on this site. I'm hooked on silencing now!

My CPU was purchased in February so it defaults to the older version of Cool n Quiet (800Mhz low power state at higher voltage). I am running Windows Server 2003 and the CnQ driver doesn't seem to work properly. My cooler is a Swiftech MCX6400V. I was running a Silenx thermistor fan and am now trying it with a Panaflo L1A (PWM controlled).

The cooler is quiet and the CPU usually stays between 55-60C when Folding @ default voltage + silenx. I tried to undervolt and was able to reduce Vcore to 1.4 volts reliably. This roughly 10% decrease dropped temps by ~4C. I couldn't go any lower without getting Machine Check Error warnings.

I noticed ClockGen and decided custom underclock my box.
http://www.cpuid.com/clockgen.php

After re-enabling CnQ in the Bios, I was able to get as low as 1.075 Volts @ 200x 7 (1.4 ghz). At this setting the CPU stays within 2 - 4C of "mobo temp" if the panaflo is @ 12V. The difference is much higher @ 7V--more like 10C. This isn't all too impressive except that the case temps have dropped too so the system is much cooler overall. I suppose the swiftech isn't exactly the best ultra-low airflow cooler. Maybe next time I'll try an exhaust-ducted Alpha. Of course, my next mission is to reduce HD noise! My 15k3 scsi drive might force me to apply some form of accoustic damping to my 3700BQE.

Anyway, I just wanted to say that you are not limited by the default CnQ settings when undervolting your A64. The advantage of this method is you get to choose exactly when (and by how much) your box speeds up. My box was stable and quiet before, but the temps made me a little uneasy. Now my temperatures are awesome.


*Note: The temps are here just to give a general idea of the reduction that is possible. There are no hard temperature comparisons because my system is always in state of change and the only tool I have for temp monitoring is Asus Probe software. I swapped between Silenx and Panaflo fans and also reapplied AS5 last night.

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K8V Deluxe, A64 3200+, 2x512 PC3200 ECC, 9700Pro, SP1213N, 36.7GB 15k3, LiteOn 16x DVD,
2 x 120mm AOC "M" Aluminum fans, Swiftech MCX 6400V +L1A, 3700BQE, SL350S + L1A, Zalman ZM80C + L1A


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 Post subject:
PostPosted: Sat May 29, 2004 2:16 am 
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Joined: Sun Feb 23, 2003 12:22 pm
Posts: 208
Location: The Netherlands
It's a pity you have the older stepping of this CPU.
I can go down to 0.85 volts @ 5*200 = 1000 MHz with the CG stepping.
This is an awsome CPU.

Have fun! 8)

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MSI K8T Neo-FIS2R
AMD64 3000+ with ducted Zalman 7000A CU, 2 Panaflo L1A fans in tandem @ 6 volts
NVidia 5200
AOpen 350 Watts PSU (AO350-12APFN) modded with 'Nexus real silent' 120mm fan (1000 RPM max)
1 Samsung 1614N + 2x Samsung 1614C
1 'Nexus real silent' 120mm casefan (front) @ 6 volts


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 Post subject:
PostPosted: Sat May 29, 2004 3:35 am 
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Joined: Fri Aug 29, 2003 12:26 pm
Posts: 66
Quote:
SpyderCat

I can go down to 0.85 volts @ 5*200 = 1000 MHz with the CG stepping.
This is an awsome CPU.


How do you identify the CG stepping?
And how does it differ from th 35 watt mobile Athlon 64 chip?


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 Post subject:
PostPosted: Sat May 29, 2004 5:19 am 
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Joined: Sun Feb 23, 2003 12:22 pm
Posts: 208
Location: The Netherlands
mikellpp wrote:
Quote:
SpyderCat

I can go down to 0.85 volts @ 5*200 = 1000 MHz with the CG stepping.
This is an awsome CPU.


How do you identify the CG stepping?
And how does it differ from th 35 watt mobile Athlon 64 chip?


It's printed on the heatspreader, and CPU-Z tells you what stepping it detected.
Image

Here it is, running Prime95 and Folding at the same time.
CPU temps 38° (diode by MBM)


Know nothing about a mobile Athlon64, sorry :?

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MSI K8T Neo-FIS2R
AMD64 3000+ with ducted Zalman 7000A CU, 2 Panaflo L1A fans in tandem @ 6 volts
NVidia 5200
AOpen 350 Watts PSU (AO350-12APFN) modded with 'Nexus real silent' 120mm fan (1000 RPM max)
1 Samsung 1614N + 2x Samsung 1614C
1 'Nexus real silent' 120mm casefan (front) @ 6 volts


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 Post subject:
PostPosted: Sat May 29, 2004 6:32 am 
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Joined: Fri Aug 29, 2003 12:26 pm
Posts: 66
Quote:
It's printed on the heatspreader, and CPU-Z tells you what stepping it detected.


I found the AMD spec for CG stepping for Athlon64 3000
ADA3000AEP4AR

2000 MHz
1.50 V
57.8 A
89 W
0.31°C/W

1800 MHz
1.40 V
45.6 A
66 W

1000 MHz
1.10 V
18.0 A
22 W

i could not find any ADA3000AEP4AR for sale at newegg, pricewathc, etc.

I assume this is the Athlon64 you have. Where did you get it?


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 Post subject:
PostPosted: Sat May 29, 2004 1:11 pm 
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Joined: Fri May 21, 2004 10:49 am
Posts: 40
SpyderCat wrote:
It's a pity you have the older stepping of this CPU.
I can go down to 0.85 volts @ 5*200 = 1000 MHz with the CG stepping.
This is an awsome CPU.

Have fun! 8)


Haha, DAMN YOU!
Instant BSOD/Reboot at around 0.9 volts for me! I guess that's what I get for buying a CPU before it is "mature."

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K8V Deluxe, A64 3200+, 2x512 PC3200 ECC, 9700Pro, SP1213N, 36.7GB 15k3, LiteOn 16x DVD,
2 x 120mm AOC "M" Aluminum fans, Swiftech MCX 6400V +L1A, 3700BQE, SL350S + L1A, Zalman ZM80C + L1A


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 Post subject:
PostPosted: Sun May 30, 2004 3:06 am 
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Joined: Mon May 24, 2004 10:42 pm
Posts: 216
Location: Canada
hydroxyhydride wrote:
SpyderCat wrote:
It's a pity you have the older stepping of this CPU.
I can go down to 0.85 volts @ 5*200 = 1000 MHz with the CG stepping.
This is an awsome CPU.

Have fun! 8)


Haha, DAMN YOU!
Instant BSOD/Reboot at around 0.9 volts for me! I guess that's what I get for buying a CPU before it is "mature."


Have you tried dropping the speed down to 1 Ghz to see if you can't get vcore a bit lower still?


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 Post subject:
PostPosted: Sun May 30, 2004 11:22 am 
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Joined: Fri May 21, 2004 10:49 am
Posts: 40
0.9V BSOD was @ 1 ghz
I may be able to take the Vcore a little lower but there seems to be a point of diminishing returns. I'm back at 1.4V experimenting with a ghetto duct I made from a 2-liter coke bottle--but it doesn't seem to be going so well. Rear exhaust is now the CPU intake and the front intake fan has been swapped so it is blowing out. CPU is cooler but I the system temp is up a lot. Maybe if I had a VGA Silencer instead of my ZM80C and I used an ALPHA to exhaust the CPU things would be better. However, these experiments are meaningless until I can quiet my hard drives. ...

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K8V Deluxe, A64 3200+, 2x512 PC3200 ECC, 9700Pro, SP1213N, 36.7GB 15k3, LiteOn 16x DVD,
2 x 120mm AOC "M" Aluminum fans, Swiftech MCX 6400V +L1A, 3700BQE, SL350S + L1A, Zalman ZM80C + L1A


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 Post subject:
PostPosted: Mon May 31, 2004 7:06 am 
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Friend of SPCR

Joined: Mon Apr 28, 2003 4:37 am
Posts: 1310
Location: Finland
hydroxyhydride wrote:
0.9V BSOD was @ 1 ghz

Since You have the older revision (the one that is on the market ATM), shouldn't You underclock it to 800 MHz? Maybe You'd get lower (but this is really a moot point). Or is there some other limits that I'm not aware of?

Cheers,

Jan

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 Post subject: How low can you go?
PostPosted: Wed Jun 16, 2004 2:32 am 
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Joined: Mon Mar 24, 2003 12:36 pm
Posts: 66
Location: UK
For reasons illustrated in http://www.silentpcreview.com/article164-page1.html I was wondering what the minimum voltage/clock is with A64s. Are these systems useable for Word, etc at for example 0.8v/300MHz.

:)

Mark


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 Post subject:
PostPosted: Tue Jun 22, 2004 2:54 am 
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Joined: Fri May 21, 2004 10:49 am
Posts: 40
Well the minimum multiplier I am able to find using ClockGen is 4 (which means 800 mhz). I don't think you can get the system at 300mhz as that would mean a multiplier of 1.5 --and I haven't found a way to make that happen yet.

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2 x 120mm AOC "M" Aluminum fans, Swiftech MCX 6400V +L1A, 3700BQE, SL350S + L1A, Zalman ZM80C + L1A


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 Post subject:
PostPosted: Tue Jun 22, 2004 4:41 am 
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Joined: Tue Jun 22, 2004 4:29 am
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[quote="SpyderCat"]I can go down to 0.85 volts @ 5*200 = 1000 MHz with the CG stepping.
This is an awsome CPU.
quote]

Can you run this CPU with passiv cooling?
It should have a tdp of under 15W so the chances are good:
89W * (0.85 / 1.5)^2 * (1000 / 2000) = 14.3W

/Morty


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 Post subject:
PostPosted: Thu Jun 24, 2004 5:13 pm 
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Joined: Mon May 24, 2004 10:42 pm
Posts: 216
Location: Canada
hydroxyhydride wrote:
Well the minimum multiplier I am able to find using ClockGen is 4 (which means 800 mhz). I don't think you can get the system at 300mhz as that would mean a multiplier of 1.5 --and I haven't found a way to make that happen yet.

Also, doesn't it kind of defeat the purpose of buying this lovely powerful 64-bit machine, to be running at 300 Mhz?


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 Post subject:
PostPosted: Sun Dec 19, 2004 7:53 am 
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Joined: Wed Dec 15, 2004 5:45 pm
Posts: 145
Location: system
I've just bought my first A64. It's Newcastle, DH7-CG. I was testing it to find lowest voltages on every freqency. I was satisfied if it pass one hour or more i prime95.
To be more precise, my mobo (Chaintech VNF3-250) overvolts a little bit under heavy load, but that overvolt is quite small 0.000V @~0.800V, 0.025V @~1.100V, 0.050V @~1.5V.

Here's graph:

Image

:lol:


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 Post subject:
PostPosted: Sun Dec 19, 2004 5:50 pm 
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Joined: Sun Sep 19, 2004 1:05 pm
Posts: 419
Location: Palo Alto, CA
My A64 Mobile 2700+ is running @ 0.8v/800Mhz. Using CrystalCPUID, it speeds itself up to 1.1v/1.6Ghz within 10ms based on demand.

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 Post subject:
PostPosted: Sun Dec 19, 2004 8:19 pm 
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Joined: Wed Dec 15, 2004 5:45 pm
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Location: system
Well, my CPU is not the mobile one and I still have better voltages :P

I can run it rock stable @ 0.8V/1GHz and up to 1.9GHz @ 1.1V

:D :D :D


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 Post subject:
PostPosted: Mon Dec 20, 2004 2:14 pm 
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Joined: Sun Sep 19, 2004 1:05 pm
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Location: Palo Alto, CA
Yep, mine is the 130nm, and you have the 90nm. I can't believe it's outdated already!

I can't go over 1.6Ghz, as that's the stock speed for my CPU, and it was stable at that speed @ 1v, but it spends such little time there, I figured the overhead wouldn't hurt.

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 Post subject:
PostPosted: Mon Dec 20, 2004 5:32 pm 
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Joined: Wed Dec 15, 2004 5:45 pm
Posts: 145
Location: system
No, I have Newcastle - it's 130nm and Winchester (90nm) is not yet released for Socket 754.

The fact I can run my CPU at lower voltages than you is that I run it out of specification and you would be probably able to achieve similar voltages with your mobile (maybe even lower). Give it a try!

You can go much further than 1.6GHz with your CPU by riseing FSB. If you have week RAM that wouldn't go over 200MHz just put it in 166MHz mod. It will run at FSB*166MHz/200MHz and it would be about 200MHz if you overclock FSB to 240MHz. CPU would be on 1920MHz at that moment.

:wink:


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 Post subject:
PostPosted: Mon Dec 20, 2004 8:47 pm 
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Joined: Fri Dec 26, 2003 6:54 am
Posts: 3022
Location: Sweden
I think the new [url=http://www.amd.com/us-en/Processors/ProductInformation/0,,30_118_10220_10221^11030,00.html]mobile A64[/url] have started to show up. They're called Oakville, not Winchester, right?

Does anyone know the OPN codes for these 35 W mobile 90 nm? I've found AMD3000BKX4LB but I'm really not sure what it is.
1.2 V should be the "Q", not "K" (ok, maybe they've changed Vcore just like they did with S939 90 nm, when looking at Fab51 it seems like they might use 1.35 V), and what is "LB"?? If it's a revision D core then it should be "B(x)", like "BI" AFAIK. I've found them here (also 2800+ and 2700+):

FrontierPC (Canada)
ITButikken (Denmark)
Verkkokauppa (Finland)

Also mentioned here:
Seagate
Chipworks

The problem is just how to find a S754 mobo that will work properly with BOTH 90 nm and mobile CPUs.... :shock:


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