The New Rebels Haven Forum!!: k7s5a - drop vcore to 1.2 -1.1V

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Topic: k7s5a - drop vcore to 1.2 -1.1V

Mile
New Member
Member # 2274

posted

Hello

My old K7s5a is lying around and I wanted to replace my file-server ( celeron 600 ) with this motherboard and TBred-B 1700+.

Because of power consumption I wanted to underclock this CPU to 800-900MHz with lowered Vcore. This board used to be overclocking one ( VCore and multiplier mod was done), but now I want to go in another direction [Smile]

Is it possible?

Posts: 12 | From: Slovenia | Registered: Dec 2005

Keh
Bronze Member
Member # 416

posted

Well, running the CPU at a FSB of 100 is right in the BIOS and if you want more flexibility, try Speedfan.

Posts: 385 | From: The Great White North | Registered: Jan 2004

Mile
New Member
Member # 2274

posted

just dropping FSB wont do much about power consumption , vcore is essential

and I am using linux for OS...

I found something

http://fab51.com/cpu/barton/athlon-e23.html#L11

Posts: 12 | From: Slovenia | Registered: Dec 2005

Mile
New Member
Member # 2274

posted

it's working. I modified L11 bridges for default core voltage 1.1V. It didn't wake up on such love voltage ( before I set it to 11x100Mhz ) so I raised it to 1.2V ( thanks to vcore mod [Big Grin]

) and it is working perfectly. I will play a little bit more to find perfect combination

http://www.silentpcreview.com/article102-page1.html

Posts: 12 | From: Slovenia | Registered: Dec 2005

Keh
Bronze Member
Member # 416

posted

quote:
just dropping FSB wont do much about power consumption , vcore is essential

Ah, so dropping the power to 68% (90/133) is insignificant but dropping it to 64% (1.2^2/1.5^2) is worthy of note.

Nice to know where the threshold lies... [Big Grin]

Posts: 385 | From: The Great White North | Registered: Jan 2004

Mile
New Member
Member # 2274

posted

quote:
Another important consideration is that power consumption gets reduced by voltage not in a linear way (as does with frequency), but by its a squared. So undervolting is much more dramatic in reducing power than lowering the clock frequency.

Posts: 12 | From: Slovenia | Registered: Dec 2005

Mile
New Member
Member # 2274

posted

and default voltage is 1.6V [Wink]

Posts: 12 | From: Slovenia | Registered: Dec 2005

Mile
New Member
Member # 2274

posted

and why not run at same speed ( 1470 Mhz ) at half of original power consumption ?

Posts: 12 | From: Slovenia | Registered: Dec 2005

Keh
Bronze Member
Member # 416

posted

quote:
Another important consideration is that power consumption gets reduced by voltage not in a linear way (as does with frequency), but by its a squared.

What part of "^2" in the formula (1.2^2/1.5^2) do you not understand?

quote:
default voltage is 1.6V

1700+ TBred-B came in two flavours "U" @ 1.6V, "L" @ 1.5V. See http://www.amd.com/gb-uk/assets/content_type/DownloadableAssets/K7_Electrical_Specification_Rev_ENG.pdf

quote:
and why not run at same speed ( 1470 Mhz ) at half of original power consumption?

Now you are just being silly - don't you think that if the CPU could run at rated speed at a lower voltage, then THAT IS WHAT THEY WOULD HAVE SET AS THE 'DEFAULT' VOLTAGE!

I'd suggest you stop digging....

(The point of my previous response was to highlight the foolishness of making 'blanket' generalizations.)

Posts: 385 | From: The Great White North | Registered: Jan 2004

Mile
New Member
Member # 2274

posted

quote:
What part of "^2" in the formula (1.2^2/1.5^2) do you not understand?

my mistake, didn't see that

quote:
1700+ TBred-B came in two flavours "U" @ 1.6V, "L" @ 1.5V. See

my is 1.6V, OK ?

quote:

Now you are just being silly - don't you think that if the CPU could run at rated speed at a lower voltage, then THAT IS WHAT THEY WOULD HAVE SET AS THE 'DEFAULT' VOLTAGE!

cores come in diferent quality, OK ? This one can reach 2.4GHz, so it is one of the best

AND it CAN run at 1400 MHz with just 1.2V, it's under full load for over 20h

Posts: 12 | From: Slovenia | Registered: Dec 2005

Keh
Bronze Member
Member # 416

posted

quote:
cores come in diferent quality, OK ? This one can reach 2.4GHz, so it is one of the best

AND it CAN run at 1400 MHz with just 1.2V, it's under full load for over 20h

Glad to hear it, but again, one must not use a singular individual experience to assume/imply that any T-Bred(B) will run at 1467 MHz on 1.2V.

(Wasn't your original statement that "I wanted to underclock this CPU"?) [Big Grin]

Posts: 385 | From: The Great White North | Registered: Jan 2004

Mile
New Member
Member # 2274

posted

ok, lets stop this pointless arguing...

my goal was to put this board in my "file-server/AP/router box",
which must be quiet, low power...

I came here( look topic title ) to get information how to drop vcore on this board because all information on the internet was how to raise it... I know how to change multiplier and FSB on this board [Smile]

And my findings are, that this is pretty easy to do with L11 bridges

You "must" agree that is better option to drop vcore and leave frequency the same than the other way. I could do both...

It is Friday night,I am going [40 Beers]

Posts: 12 | From: Slovenia | Registered: Dec 2005

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