BIOS and Overclocking

The BIOS of EPoX 9NPA+ Ultra is based on the microcode from Award-Phoenix and has the ordinary interface with all the necessary options for configuring the buses and the peripherals. Added to the basic features is EPoX’ exclusive Magic Health technology – when passing the POST procedure, the mainboard can show onscreen not only the basic parameters of the CPU and memory, but also information about the temperatures, fan speeds and voltages. This is especially useful for overclockers as you can have a comprehensive view of your system status before even the OS boots up.

Let’s get right to the overclocking-related options of the BIOS Setup since EPoX positions its product as an overclocking-friendly mainboard. The speedup options are found on the Power BIOS Feature page.

When on this page, you can do the following:

• Change the frequency of the CPU clock generator from 200 to 400MHz with 1MHz increment;
• Independently adjust the frequency of the PCI Express bus from 100MHz to 145MHz with 1MHz increment;
• Select the memory frequency from a list of standard values: 100/133/166/200MHz for DDR200/DDR266/DDR333/DDR400 SDRAM;
• Manually reduce the CPU frequency multiplier (8x is the smallest value);
• Increase the CPU voltage above the default by 0.35V with 0.025V increment;
• Manually select the memory voltage, from 2.5V to 3.1V with 0.1V increment;
• Increase the chipset voltage from the standard 1.5V to 1.8V with 0.1V increment.

As you see, EPoX did its best to please overclockers; the BIOS Setup of EPoX 9NPA+ Ultra has everything necessary to give a speed boost to your processor as well as to your memory. Besides changing the memory frequency, you can manually select the timings Tcl, Trcd, Tras, Trp, and choose the 1T/2T Memory Timings mode.

Well, an abundance of overclocking-related options in the BIOS Setup doesn’t guarantee that the actual overclocking will go smoothly. So, we can’t move along without checking the maximum possible frequency of the clock generator in practice. We took an Athlon 64 3800+ CPU (2.4GHz frequency) and reduced its multiplier to 8x. In order to prevent the memory potential from limiting our overclocking results, we reduced the memory frequency to the values it was sure to support.

So, here is the description of our overclocking experiments. Right from the start we managed to raise the frequency of the clock generator from the default 200MHz to 240MHz. At this clock rate, the system wouldn’t start up at all, not to mention booting up the OS. But we were sure we didn’t hit the limit since the stability had been excellent at 239MHz. So, we began to search for the limiting factor.

An increase of the chipset voltage from 1.5V to 1.7V gave us little hope: the system started but the clock frequency generator showed 240MHz. However, it was a way too early to celebrate: the system couldn’t pass the POST procedure at 242MHz already.

The real limiting factor was easy to identify, though. It was the HyperTransport bus which frequency grew up too much since we left its multiplier at default (5x). Fortunately, EPoX 9NPA+ Ultra offers you the control over the HyperTransport multiplier, and we dropped it from 5x to 4x.

The mainboard woke up after that and we could continue our overclocking tests. The nest time we faced stability problems the clock generator frequency equaled 289MHz. Remembering our previous experience, we simply reduced the HyperTransport multiplier again, bringing it down to 3x.

Of course, it helped again. We managed to reach 301MHz on the clock generator. Although the HyperTransport bus didn’t seem to be a limiting factor anymore, the reduction of its multiplier to 2x helped again.

With this multiplier we continued our overclocking till we met the frequency ceiling of the CPU. So, our experience suggests that EPoX 9NPA+ Ultra is capable of working at frequencies of the clock generator above 300MHz. The only factor that hinders this overclocking is the growth of the frequency of the HyperTransport bus above its default 1000MHz. If you reduce the frequency multiplier of this bus, your overclocking won’t be limited at all on the EPoX 9NPA+ Ultra.