Asus P4B266-E and P4S333 in the test: Intel 850 versus Intel 845 and SiS 645

Asus P4B266-E and P4S333 in the test: Intel 850 versus Intel 845 and SiS 645


We had absolutely nothing to complain about in terms of the stability of the P4B266-E. We were able to choose the sharpest settings for the RAM and also increased the voltage for the DDR RAM to 2.7 volts. And even with these quickest possible settings, the board performed its service absolutely flawlessly. We didn't have to complain about a single crash during our test period and all components ran without any problems despite the wealth of additional features. The typical Asus features like 'EZ Plug', the 'Asus Post Reporter', 'Asus Update' and 'MyLogo' worked perfectly.

The 'Post Reporter' issued the predefined reports for each occasionand gave the correct voice messages in our tests without booting RAM or 12V plug.

In terms of stability, the P4B266-E was therefore able to convince completely. Nowadays you shouldn't expect anything else from a board in this price range and from a brand manufacturer like Asus.


With overclocking, Asus goes the well-known way and divides these functions into Bios and Jumper on.

The VDimm voltage (2.5-2.7V) can still only be increased using a jumper on the board. However, you have to reproach Asus with a little carelessness in the documentation. The jumper for increasing the VDimm voltage is documented, but no information can be found anywhere as to how high the voltage is actually increased when the jumper is repositioned. It takes a lot of effort to get the applied voltage out yourself. Unfortunately, the VDimm voltage can only be changed using a jumper on the board. A simple option for this is missing in the bios.

With the front-side bus and multiplier, you can choose between bios or jumpers. They can either be switched using a jumper on the board, or conveniently in the BIOS, if the board is set to 'Jumper Free' mode using a jumper, as it is supplied as standard. If you choose the 'Jumper Mode', the settings are made via DIP switches. Of course, due to the limited possibilities of a DIP switch, the BIOS offers more extensive options.

The FSB in the BIOS can freely choose from 100-200MHz in 1MHz steps and the multiplier from 8.0x to 24, 0x can be freely set at intervals of 1.0. However, this only comes into play with 'unlocked' Pentium4 processors that cannot be bought in stores. So that the DDR-RAM is not only addressed with 100MHz, the clock ratio can be changed from 1: 1 to 4: 3, so that the FSB is 100MHz, but the RAM is operated at 133MHz.

Since the Pentium4 only allows successful overclocking via the FSB, it is a pity that the P4B266-E there is no function to keep the PCI and AGP clock fixed at 33 or 66MHz. Unfortunately, if you increase the FSB, the PCI and AGP clocks also increase accordingly, which can quickly put an end to overclocking sensitive components. At least with an FSB of 133MHz, the divider jumps and delivers again 33 or 66MHz for the PCI and AGP clock, so that the P4B266-E is theoretically suitable for the new Pentium4 with 133MHz FSB.

The core voltage can be increased in the BIOS from 1.5 to 1.7 volts in 0.025 volt intervals. If you put an over-volt jumper on the board, you can increase the core voltage in the BIOS up to 1.75 volts. With the Willamette, you can also choose between 1.75 and 1.85 volts in 0.025 intervals. With the over-volt jumper you can even reach up to 2.1 volts.

With the memory timings, you will find the usual setting options in the BIOS. You can either leave the configuration to the SPD (Serial Presence Detect) or you can do it yourself. You can change the “CAS Latency” from 2.5T to 2.0T, the “RAS to CAS Delay” from 3T to 2T, the “RAS Precharge Delay” from 3T to 2T and the “Active Precharge Delay” from 6T to 5T reduce. In addition, you can choose between 0T, 8T, 16T, 64T and Infinite for the “Idle Timer”. Only the 'Command Lead-Off Time' cannot be adjusted in the BIOS. In our test the memory ran with the timings 2,2,2,5.

In the BIOS we had to also notice the only real fault of the P4B266-E. You can choose between 4, 8, 16, 32, 64, 128 and 256MB for the “AGP Aperture Size”, but a change in this value does not seem to have any influence on the actual “AGP Aperture Size”. The 'AGP aperture size' was for usAccording to various tools for reading always 256MB, no matter what size we set in the BIOS. The option is therefore simply useless, since a change has no effect.

FSB check: This time we checked the FSB for correctness. Actually, 100.9MHz FSB in itself offers little reason for complaint, but this value is of course multiplied enormously with the Pentium4. These 100.9MHz FSB already result in 403.59MHz with the Quad-Pumped-Bus and with a multiplier of 20 with our Pentium4 2.0A we already have 2017.96MHz. All in all, you are 18MHz away from the standard value. We will clarify in our next review whether other manufacturers can more precisely match the pace of the Pentium4.

On the next page: The P4S333