BIOS and Overclocking

Chaintech positions its Zenith series mainboards as platforms for PC enthusiasts. Keeping this fact in mind, I hoped to find rich overclocking options in the BIOS Setup of the Chaintech Zenith ZNF3-250 mainboard. My expectations came true.

All overclocking-related options are gathered in the BIOS Setup of the mainboard, in the Frequency/Voltage Control page:

Let me describe the options in detail:

• You can change the FSB frequency. The range formally stretches from 200 to 400MHz with 1MHz increment. Considering that nForce3 250 chipset allows locking the AGP/PCI clock rates, this widest range may be not just a marketing trick. However, this is spoiled by the fact that Chaintech Zenith ZNF3-250 doesn’t allow reducing the CPU multiplier. That’s why this highest FSB frequency ceiling turns to be quite useless;
• The AGP clock rate can be set up independently from 66 to 100MHz with 1MHz increment. The PCI frequency equals AGP/2, i.e. is also set independently from the FSB;
• You can manually adjust the Vcore from 1.45V to 1.7V with 0.025V increment. Thus, the Vcore can be 0.2V above the rated voltage at highest. This may be not enough for good overclocking;
• You can adjust the Vmem from 2.6 to 2.9V with 0.1V increment;
• You can change the voltage on the AGP bus: from the nominal 1.5V up to 2.2V. It’s quite a mystery why we need such a high voltage on the AGP;
• You can adjust the voltage sent to the chipset. You can increase this value from the normal 1.6V to 1.7V, 1.8V or 1.9V. As you know, the option of increasing the chipset voltage is very useful for successful overclocking.

To our regret, the mainboard appeared incapable of controlling the voltage of the HyperTransport bus, but what was even worse, it didn’t allow changing the CPU multiplier in the BIOS Setup. Thus, overclockers who use Chaintech Zenith ZNF3-250 will lack operational modes with a reduced multiplier and an increased FSB frequency (over 200MHz). Such operational modes may be very interesting with respect to memory types, especially overclocker memory modules, because the maximum frequency on the memory bus that modern Athlon 64 processors support with the normal FSB frequency is only 400MHz.

As for the rest of overclocking-related capabilities, we should point out the opportunity to reset the processor parameters in case of over-overclocking. Sometimes the manufacturers forget about this option or implement it incorrectly. If you press and hold the INS key during the system boot-up process, you enter the BIOS Setup and correct the wrong parameters. Moreover, in some cases, the mainboard can reset the wrong parameters by itself, after shutting down and starting up again. The BIOS of Chaintech Zenith ZNF3-250 uses the Award microcode and has certain peculiarities. For example, you cannot disable the onboard external controllers (network, audio and SerialATA RAID ones) in the BIOS Setup. By the way, there are also no jumpers onboard to disable those devices. In other words, you can only turn them on/off in the operation system.