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In times where everybody follows the jumperless trend, it is a bit nostalgic to see a board featuring not one or two but a whole battery of jumpers. Suffice it to say that under many conditions, jumpers and switches are much preferable over any software (including BIOS)- based solution. The minor inconvenience caused by a one time enabling disabling of certain integrated peripherals is no comparison to the nuisance of a PnP OS constantly searching for additional hardware that was disabled in the BIOS but still spooks around in the background. In other words, the true art is to find a compromise between features that make sense to support in SoftBIOS mode and those that are better off by the unambiguous ways of hard setting.

Despite the fact that the A7V333, once it is up and running can be operated in jumper-free mode, the board features a gazillion of jumpers meant to enable / disable RAID, on-board sound, IEEE 1394 Firewire, USB and Keyboard Power-Up, the Secure Digital and Memory Stick media interfaces and the infamous POST Reporter which comments on the different boot processes (the last thing I personally would need but then, some like it). All in all, ASUS deserves a high commendation for this solution since it is independent of the BIOS revision and plain and simply cleaner than any soft solution. Needless to say that these jumpers don't really need any further description, the same holds for the audio bass center setting.

A small "Hors d'Oeuvre" of the jumper menu awaiting the un-expecting user of the A7V333: on the left are JP1 and JP2 to set the DDR voltages. "1" enables Power-On by USB 1 and 2, "2" and "3" are the line audio header jumpered to reroute the signals to the back panel jacks and the bass center setting, respectively. "4" and "5" are audio and Firewire enable. The Firewire connector is partially visible next to the VDDR jumpers. Also in the picture are the dip switch to manually set FSB frequency, the USB 2.0 header enabled by the VIA VT6202 controller chip. On the left of the USB chip is the TI IEEE 1394 controller, on the right is the CMedia CMI8738 6-channel sound.

There are a few other jumpers on board that deserve more attention. First, there is the known JEN jumper to enable / disable jumper-free mode. By default, jumper-free is enabled, however, in order to e.g. access the dip switch, the jumper needs to be moved.

The VID1-4 header allows hard setting of the CPU core voltage from 1.675 to 1.85V with two voltage outputs, depending on which CPU type is used. In order to really burn up the CPU, though, it is necessary to move the Voltage Regulator Output Limit jumper to the Unlimited position. In addition, the A7V333 features an undocumented Overvoltage jumper. The same jumper on the P4B266 opens up additional Vre settings in the soft BIOS, in the A7V333, moving the Overvoltage jumper simply increases the Vre by 0.3V, that is, if the Voltage Regulator Output Limit is set to "unlimited". Consequently, if the Vre is set to 1.75, the real Vre as shown by the Hardware Monitor is 2.05V. Better be careful with this one.

It gets more confusing with the ROMSIP jumper. The manual states: This jumper selects the source for data to set functional parameters fir the CPU. The default setting [1-2], enables present ROM data access from the chip. Resetting the jumper to [2-3] enables the use of BIOS to set CPU parameters. Phil Marlowe once said to me: Dead men don't wear plaid. That was 20 years ago and I still have no clue what it means. We may have some more info on this matter shortly, so stay tuned.

DDR Voltages

When it comes to running voltages out of spec, hardly any manufacturer has the kind of track record as ASUS. From the P5A to the A7M266, the road has literally been paved with burned DIMMs and the A7V333 threatens to continue this tradition.

The layout of the VDDR jumpers has been carried over from the A7V266-E, that is jumpers JP1 and JP2, only the values have changed. By default, the A7V333 supplies a whopping 2.78-2.85 VDD and VDDQ (DDR core and I/O voltage). The variation accounts for the differences in measurement on several boards. Changing the jumper configuration allows settings between 2.59 and 3.06V. The detailed settings are:

ii 2.59 - 2.63V (same with one or both jumpers removed completely)
i! 2.78 - 2.85V (default setting, out of spec according to JEDEC guidelines)
!i 2.88 - 2.96V
!! 2.95 - 3.06V

The latter two settings are almost guaranteed to destroy the memory modules, maybe not today but after a few weeks. It is not clear what the purpose of the high voltage settings is, however, it is only a matter of time until this will become a liability issue for ASUS, one way or another. Keep in mind that the settings are not documented and the high settings are not meant for "public consumption" by ASUS either.

The interesting thing about these settings is that all current high-end DDR chips are using internal voltage regulators to reduce the core voltage to 1.8V which is necessary to run at high frequency. The only parts of the chips that actually see the increased voltage are input/ output buffers and, granted that those will wiggle a bit faster at higher voltages, the net effect is counteracted by the fact that the internal voltage regulators produce a lot of heat that will overall slow down the chips. In other words, a sensitive approach would be to leave VDD alone but increase VDDQ. Admittlely, there are some older DIMMs that will run at 2.5V internally but those will hardly be used in PC2700 mode of operation which is the only scenario where the massive overvoltage would be of benefit.

The recommendation in this case is, similar as what we suggested for the A7M266: simply take off both JP1 and JP2 to bring the voltages back to where they belong. Side effects are that the failure rate, that is, stuck bits and system crashes in memory-intensive applications go down quite dramatically. In addition, we saw up to 3 % system performance increase in Expendable at the lower voltage. It is not completely clear what causes this performance increase but any electronics will run faster and cleaner when they run cooler.

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