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Hello, this is my first thread here.
I bought a 525 Board and was not really satisfied with the overall power consumption:
I got 2x1GB RAM, and one Western Digital Eco HDD and one PCI Soundcard (RME DIGI 96). The Mainboard is powered by a pico PSU, which transforms 12V to 3,3 and 5V. The whole system needed 32-36W out of the plug.
Thats only 10W less what my old P III do consume, and 10W less than a Core 2 Duo in an Dell Optiplex 745.
The Problem is, that the MB gives several overclocking and overvolting features but no undervolting ability!
So i searched for the voltage Regulator Manual in the WWW
The Power Regulation of the 525:
There are two APW 7120 onboard. One is for the CPU 1,1V Voltage, the other is for the 1,8V DDR Voltage.
The 1,5V and 1,05V is made with a linear regulator made of a quad opamp and a couple of fets. Those linear regulators are fed from the DDR Voltage as i think.
Lowering the DDR voltage will also lower the power destroyed in those regulators.
The Datasheet of the APW 7120 is aviable here:
APW7120 datasheet pdf datenblatt - Anpec Electronics Coropration - 5V to 12V Supply Voltage, 8-PIN, Synchronous Buck PWM Controller ::: ALLDATASHEET :::
Modifications:
As you can see in the Datashet, the voltage is defined by a resistor feetback network. I did not manage to understand the whole schematics on the MB, but i noticed that it's really easy to modify the feedback.
If you increase the feedback with a smaller resistor R1 (see schematics pdf) you get a lower voltage.
So i soldered a Poti from the VT1 Pin to Pin 6 of the AWP 7120.Adjusting it to around 50 Ohm yields a V-core of 0,85V-0,87V. And the CPU runs stable at 1,8GHZ! So i changed the pot to a 57Ohm Resistor.
The Bad thing is, that the overvolting function is less intense.
The second thing is, that i did some modifications of the DDR voltage. I use my old overclocking RAM (ADATA Extreme Edition), which is able to run at 1GHZ. Here I did the same thing than to the cpu voltage: put a pot between VT2 and Pin 6. This time a resistance around 1,5k gives 1,5V DDR Voltage. I did not have a 2K Resistor here, so i let the RAM run at 600Mhz and it's rock stable.
Ok, is it worth using the soldier gun? Yes it is!
The whole PC needs 22W !
As you can read in the Atom Datasheet, the VID goes from 0,8V to 1,2V. I think Asrock did not use the VID and let every CPU run at 1,1V. So there is a good chance to get a fine undervolting result.
I don't whant to write a "exact" diy manual, because i don't whant to risk that someone who is not familiar with hardware modding tries this.
I bought a 525 Board and was not really satisfied with the overall power consumption:
I got 2x1GB RAM, and one Western Digital Eco HDD and one PCI Soundcard (RME DIGI 96). The Mainboard is powered by a pico PSU, which transforms 12V to 3,3 and 5V. The whole system needed 32-36W out of the plug.
Thats only 10W less what my old P III do consume, and 10W less than a Core 2 Duo in an Dell Optiplex 745.
The Problem is, that the MB gives several overclocking and overvolting features but no undervolting ability!
So i searched for the voltage Regulator Manual in the WWW
The Power Regulation of the 525:
There are two APW 7120 onboard. One is for the CPU 1,1V Voltage, the other is for the 1,8V DDR Voltage.
The 1,5V and 1,05V is made with a linear regulator made of a quad opamp and a couple of fets. Those linear regulators are fed from the DDR Voltage as i think.
Lowering the DDR voltage will also lower the power destroyed in those regulators.
The Datasheet of the APW 7120 is aviable here:
APW7120 datasheet pdf datenblatt - Anpec Electronics Coropration - 5V to 12V Supply Voltage, 8-PIN, Synchronous Buck PWM Controller ::: ALLDATASHEET :::
Modifications:
As you can see in the Datashet, the voltage is defined by a resistor feetback network. I did not manage to understand the whole schematics on the MB, but i noticed that it's really easy to modify the feedback.
If you increase the feedback with a smaller resistor R1 (see schematics pdf) you get a lower voltage.
So i soldered a Poti from the VT1 Pin to Pin 6 of the AWP 7120.Adjusting it to around 50 Ohm yields a V-core of 0,85V-0,87V. And the CPU runs stable at 1,8GHZ! So i changed the pot to a 57Ohm Resistor.
The Bad thing is, that the overvolting function is less intense.
The second thing is, that i did some modifications of the DDR voltage. I use my old overclocking RAM (ADATA Extreme Edition), which is able to run at 1GHZ. Here I did the same thing than to the cpu voltage: put a pot between VT2 and Pin 6. This time a resistance around 1,5k gives 1,5V DDR Voltage. I did not have a 2K Resistor here, so i let the RAM run at 600Mhz and it's rock stable.
Ok, is it worth using the soldier gun? Yes it is!
The whole PC needs 22W !
As you can read in the Atom Datasheet, the VID goes from 0,8V to 1,2V. I think Asrock did not use the VID and let every CPU run at 1,1V. So there is a good chance to get a fine undervolting result.
I don't whant to write a "exact" diy manual, because i don't whant to risk that someone who is not familiar with hardware modding tries this.
