<!–#set var="article_header" value="Tuning Extreme:
Overclocking with the Asus A7V” –>
Processor Tuning: Asus A7V at the limit
We already described the extensive overclocking possibilities for the Asus A7V in the article Modifying An Asus A7V Motherboard For Duron-Overclocking. Today we demonstrate a method that takes the clock frequency to the extreme but keeps the processor at a stable level.
This requires a slight modification of the motherboard, however. By following the instructions below you can alter any Asus A7V to enable perfect overclocking of AMD’s Athlon and Duron processors.
We have put it to the test: After the retrofit a Duron 750 runs totally stable at 1000 MHz! An Athlon 1000 even reaches 1133 MHz. You will need a little experience with the soldering iron to make this very simple alteration.
Prerequisites for successful tuning
The basis for successful overclocking is an Asus A7V with an additional DIP-switch for changing the clock multiplier. Lately the manufacturer puts this switch on current board versions.
A few conditions must be met before an AMD Athlon or Duron can be pushed to its limit. First you need an Asus A7V that has the additional DIP-switches for adjusting the clock multiplier.
There are two possible scenarios: If the board is already equipped with the DIP-switch quit works, no further action is required. If the DIP-switch is missing, it must be added besides two other components – as described in the article Modifying An Asus A7V Motherboard For Duron-Overclocking.
The processor that is going to be overclocked must also meet a few requirements: The L1 bridges on the ceramic body of the CPU should be closed. If they are open, you can use a pencil to close them.
The voltage controller of the Asus A7V resides on a separate circuit board. It generates a standard maximum core voltage of 1.85 Volts.
CPU core voltage as the limiting factor
The core voltage is the limiting factor for overclocking AMD’s Duron and Athlon processors. Because the four voltage IDs are fixed, AMD specifies 1.85 Volts as the highest adjustable core voltage. Therefore the AMD Athlon 1000 for example, which requires a standard voltage of 1.8 Volts, can hardly handle higher clock frequencies because the voltage cannot be increased.
Significant increases in clock frequency can be achieved if the core voltage is raised beyond 1.85 V, especially in combination with a powerful heat sink and fan.
The situation is identical with the ever-faster Duron processors: they require a higher voltage for overclocking to operate at a stable level. Even 1.85 V are not always sufficient. Using the Asus A7V as example we demonstrate how the core voltage can be raised with small modifications.
These utensils are required for modifying the motherboard: A soldering iron with a fine tip, solder, and a resistor with 24 KOhm (performance class 1/4 Watts).
This picture shows the modification of the controller IC on the VRM module of the Asus A7V. The 24 KOhm resistor distorts the input signal at the controller IC and increases the CPU core voltage.
Building instruction: A maximum core voltage of 2.32 Volts
Before we begin with the actual modification, you should have the following utensils ready:
- Low-power soldering iron with a fine tip
- Resistor with 24 KOhm (performance class 1/4 Watts)
On the Asus A7V the VRM module resides on a separate circuit board. With a resistor we create an additional connection to this controller IC, which enables higher CPU core voltages. To explain it in more detail: A controller IC (CS5322) sits next to the MOSFET transistors on the small switch controller board.
This circuit controls the MOSFET transistors, which receive digital input signals from the CPU. The 24 KOhm resistor that is connected to the input part of the controller IC distorts the incoming control signal from the CPU. The result: The MOSFET transistors send a higher core voltage to the CPU.
Installing the resistor changes the core voltage, which means the preset values in the Asus A7V BIOS do not match the actual voltages. This problem can be addressed with our table that contains the adjusted voltages in relation to the values in the BIOS.
Small modification – big effect: A 24 KOhm resistor is soldered to these two pins. Attention: SMD resistors that do not tolerate too much heat are connected to both pins.
Top view of the modified VRM module: The resistor has been soldered in and generates a permanent core voltage of up to 2.32 Volts.
Choosing the correct core voltage
To make setting the correct core voltage a bit easier we put together a table with all the exact voltages. After the installation of the resistor the lowest voltage is 1.37 Volts, while 2.32 Volts is the maximum voltage. According to our experience no processors should be operated permanently with more than 2.11 Volts. Appropriate cooling is an important factor for successful tuning when the voltage is increased. Otherwise the higher power dissipation of the processor contributes to an early death of the CPU.
CPU Core Voltage at Bios | CPU Core Voltage after Modification |
1,1 Volt | 1,37 Volt |
1,15 Volt | 1,44 Volt |
1,2 Volt | 1,47 Volt |
1,25 Volt | 1,55 Volt |
1,3 Volt | 1,61 Volt |
1,35 Volt | 1,66 Volt |
1,4 Volt | 1,72 Volt |
1,45 Volt | 1,79 Volt |
1,5 Volt | 1,88 Volt |
1,55 Volt | 1,95 Volt |
1,6 Volt | 2,03 Volt |
1,65 Volt | 2,06 Volt |
1,7 Volt | 2,11 Volt |
1,75 Volt | 2,17 Volt |
1,8 Volt | 2,24 Volt |
1,85 Volt | 2,32 Volt |
According to this table the core voltage can be increased step-by-step. Extreme caution is highly recommended with values above 2.1 Volts. This situation requires a very powerful heat sink/fan.
A frontal view of the modified VRM module: The soldering must be done very carefully to avoid destroying components of the Asus A7V.
Since the preset CPU voltage does not match the actual voltage after the resistor has been soldered in, a precise control is very important. Otherwise electro-migration caused by excessive voltages can destroy the processor core very quickly. The two pictures below show parts of two different BIOS menus. While the standard menu displays a preset voltage of 1.85 Volts, the actual core voltage is at 2.32 Volts. The power menu of the BIOS contains the exact information.
The actual core voltage can be set with the power menu in the BIOS: If the voltage is set to 1.85 Volts in the BIOS, the Asus A7V generates a maximum core voltage of 2.32 Volts after the retrofit.
The picture shows a part of the BIOS settings. Caution: After the retrofit the selected core voltages do not match the actual voltages anymore. We put together a table for adjusting the correct voltage.
AMD Duron with 1000 MHz!
In our test we achieved the fastest speed with the AMD Duron 750. At a core voltage of 2.11 Volts we reached a stable clock frequency of 1000 MHz. This resembles a clock increase of 33 %. The amount of the possible core clock increase always depends on the quality of the CPU itself.
Speed record because of voltage increase: The AMD Duron 750 is stable at 1000 MHz if the core voltage is increased to 2.11 Volts. A powerful heat sink is a must, however.
Conclusion: Higher core voltage helps CPUs to reach the limit
This relatively simple retrofit of the Asus A7V that can be done in a few minutes packs a punch: The higher core voltages of up to 2.32 Volts lets every Duron and Athlon CPU operate at the limit.
While the regular Asus A7V only offers a maximum voltage of 1.85 Volts, and most processors become unstable when overclocked, the altered board gives a very good impression. For example a Duron 750 can be overclocked 30 percent, resulting in a maximum clock frequency of 1000 MHz.
With the fast Athlon processors the possible improvements in clock frequency are rather limited, however: In our test we succeeded in running an Athlon 1000 at a maximum of 1133 MHz, always under the condition of keeping the processor safely alive and the system stable.
Nevertheless, retrofitting an Asus A7V is definitely worth it: The resistor costs less then 10 cents and the board is ready for overclocking future AMD processors past the 1000 MHz limit.