Overclocking and BIOS Settings

The VP6 was the first VIA 694X board from ABIT to feature their SoftMenu III with its 1MHz-increment front side bus "baby-stepping" feature. None of their previous "V" boards (VA6, VT6X4, VL6, VH6) had it, though the since-released VH6-II does. Presumably it was a clock-generator issue. In any case, overclocking couldn't be made any easier.

Even if you don't want to screw around with your processors' speeds, on this board you really do need to make your memory settings more aggressive. This is simple enough to do: Under "Advanced Chipset Features," there are four lines reading "DRAM Timing," corresponding to the four DIMMs. Set the banks that your memory is using to "Turbo." Set "DRAM Bank Interleave" to 4-Way, and "SDRAM cycle length" to 2. Set "Fast R-W Turn Around" to Enable, and set "Delay DRAM Read Latch" to no delay.

Overclocking the CPUs is just as easy and not really dangerous as long as you don't give them more voltage than your cooling fans can handle. To be safe, ABIT have built in an alarm (under "PC Health Status") to warn you if the temperature goes about a certain level. I keep this set to 50°C.

The speed of your CPU is the front side bus speed times a number known as the multiplier. I was using 800MHz PIIIs with a FSB of 133MHz; therefore my CPUs' multiplier was 6. I couldn't change that. However, by changing the "CPU Operating Speed" (in the SoftMenuIII menu) to "User Define," I could make sure that the "Multiplier Factor" stayed at 6, while setting the FSB (aka "Host Clock") as high as possible. 

ABIT provide two ways to do this: The "Host Clock" setting allows you to change the FSB in large increments. For example, the next setting after 133 is 140, and the next after that is 150. Since I had no problems at 140, I tried 150, but could not boot into Windows. At that point, I switched to the second method, "FSB Plus," which allows you to add 1MHz at a time to the Host Clock. When I added 1 to 140, I had no problems, so I tried 2. At 142, sometimes I was able to boot into Windows, sometimes not. I knocked it back down to 141, giving me a CPU speed of 846MHz.

To run at these increased speeds, your CPUs need a little extra juice, so I have kept the core voltage ("Vcore") up .05v above the default, and the I/O Voltage up an extra .1v.

This caused me some concern: 141 ain't really that great. I decided to find out how well the VP6 served as a single-CPU overclocking board. Individually, both of these CPUs were able to get into Windows at FSB speeds as high as 158. So why couldn't they do that together? I am aware that getting two overclocked CPUs to work together is far more difficult than getting one to operate on its own, but a cut from 948 to 856 was pretty painful. Some people have complained that the VP6's less than stellar overclocking is due in part to the absence of separate voltage adjustments for the two CPUs (a feature present on the BP6). However, I don't think that was the problem here, as both the CPUs were able to achieve 158FSB with a Vcore of 1.75.

Other BIOS tweaks:

DRAM Clock: There are three options here: Host Clock, Host Clock+PCI, or HostClock-PCI. Since PCI here is one-fourth of the FSB speed, this means you can run your memory bus at the same speed as your FSB, or else at 75% or 125% of it. My memory was PC133, but it had no problems running at 141.

Hardwired IOQ: When ABIT First introduced this on their BX chipset boards, it was called "In-Order Queue Depth." The possible settings varies depending on the chipset; with VIA 694X, we get either 4 or 1. Here higher is better. Choose 4.

AGP settings (under "Advanced Chipset Features"): If you have an AGP4X card, make sure "AGP4X" and "AGP Fast Write" are enabled. Increasing "AGP Aperture Size" and "AGP Driving Control" to their maximum will not increase performance. Leave them at auto.

Note: If you are unable to boot into Windows as a result of any of these adjustments, return to the BIOS screen and choose "Restore Default Steeings." If you can't even get into the BIOS screen, unplug your system, and move the CMOS jumper (located just south of the battery) to pins 2 and 3 for a few seconds and then back. Power your system back up, and the default settings will have been restored.