BIOS and Overclocking

BIOSes of ASUS mainboards may seem strange for users who have got accustomed to the Award microcode, but you will get used to it soon and probably like it. Other companies simply adjust the microcode from Award for each particular mainboard, while ASUS writes its BIOSes from bottom to top, with attention to each menu item and including some extras. The code usually uses the features and unofficial capabilities of the particular chipset.

I was slightly shocked when I saw the options collected in the Advanced Chipset Features page, which control the memory timings in the User Defined mode. You seldom meet such abundance:

• SDRAM Active Precharge Delay – from 1 to 15 stepping 1;
• SDRAM RAS to CAS Delay – from 1 to 7 stepping 1;
• SDRAM RAS Precharge Delay – from 1 to 7 stepping 1;
• SDRAM CAS Latency – Auto, 2T, 2.5T, 3T.

Basic overclocking-related options are also found in the Advanced Chipset Features page:

• CPU External Frequency can change from 100 to 300MHz stepping 1MHz;
• CPU Frequency Multiple – this parameter changes somewhat irregularly. You can set it to 13.0x, 13.5x, 14.0x, 6.5x, 7.0x/15.0x, 7.5x, 8.0x/16.0x, 8.5x/16.5x, 9.0x/17.0x, and from 9.5x to 12.5x stepping 0.5;
• Memory Frequency is set up in percent of the FSB clock rate: 50%, 60%, 66%, 75%, 80%, 83%, 100%, 120%, 125%, 133%, 150%, 166%, 200%;
• CPU Vcore changes from 1.5V to 1.75V stepping 0.025V;
• AGP Frequency can be given the following values: 50MHz, from 66 to 87MHz stepping 1MHz, 90, 93, 95, 97, 100MHz.
• DDR Reference Voltage – 2.6V, 2.7V, 2.8V. That’s rather a scanty choice :(
• AGP VDDQ Voltage – 1.5V, 1.6V, 1.7V. We can change the voltage on the AGP slot of the mainboard.

If you get too overwhelmed in your overclocking drive and go beyond the capabilities of your hardware, the system will either start up automatically with the default BIOS settings or wait for you to press the Ins key in the right time. By the way, we had to resort to such measures only once during our tests.

What does the BIOS of ASUS A7N8X-E Deluxe lack? What does an overclocker need? Yes, we need the option of raising the voltage on the mainboard’s North Bridge. You can’t do this with ASUS A7N8X-E Deluxe – that’s the point off the developers’ score.

Enough theory, now let’s turn to practice. Let’s try to overclock the thing. As usual, we are trying to reach the highest FSB frequency in the dual-channel synchronous mode. Regrettably, our ASUS A7N8X-E Deluxe wasn’t willing to speed up. The maximum frequency we notched when overclocking our processor was 225MHz. We booted up the OS a couple of times at higher frequencies, but the 225MHz FSB was the maximum stable clock rate. That’s right – higher clock rates require higher voltage on the North Bridge and this mainboard doesn’t allow raising that. Note that it was really the mainboard that limited our overclocking experiments as we used overclocker DDR500 SDRAM memory and locked the AGP/PCI frequencies at their normal values since ASUS A7N8X-E Deluxe supports this option.

The result of 225MHz FSB may be acceptable, though, if it were not for another problem. After working with the overclocked FSB for some time, the mainboard’s BIOS crashed. It was damaged completely, and the boot block too, leaving no hope for a simple restoration. The reanimation process was not very easy. We had to search for another mainboard like the crashed one and simply replace its BIOS chip. Then we installed the chip into the damaged mainboard and made sure that the problem was really in the damaged BIOS.  Then we had to reflash the BIOS chip on the operational mainboard, using the well-known guidelines. I should confess that the corruption of the BIOS code is an often-reported problem for mainboards on nForce2 chipset. Anyway, such a problem can discourage any user, especially a beginner, from any overclocking experiments.