Motherboard compatibility/new chips

Compatibility

Those of you with ABIT TH7II-RAID motherboards already know that your motherboard has supported the 533MHz Pentium 4 CPU for quite some time. If you recall our review of the motherboard way back in August, we complimented ABIT for providing so many bus options. Right from the start ABIT offered settings for the 2.53GHz Pentium 4 processor we’re reviewing today.

Besides the TH7II-RAID, many of the other i850 Socket 478 Pentium 4 motherboards also support the 533MHz P4 chips (albeit unofficially, as technically the chipset doesn’t support 533MHz, and some motherboard manufacturers used clock generators that may not run well at 533MHz). All you’ll need to do is download the latest BIOS for your motherboard and you’ll be good to go. The 850E chipset is identical to the original i850; the only difference is that it has been officially validated to operate at 533MHz. This means that i850E still offers official support for USB 1.1 as well as 800MHz Rambus RDRAM.

Just because i850E doesn’t officially support 1066MHz RDRAM, doesn’t mean it won’t work. In fact, 1066MHz RDRAM should work just fine in all 850E motherboards, as well as 850 motherboards like the ASUS P4T-E and ABIT TH7II-RAID.

When setting up your 533MHz system, you’ll have to make sure that your memory bus is operating with the 4.0 setting enabled to run your memory at 1066MHz. If you’re using older 800MHz RDRAM you may want to try overclocking your memory modules to 1066MHz to see if they will work. Many of the newer RDRAM modules have no problem running at that clock speed, but for proper support memory manufacturers will be releasing RDRAM modules that are officially designed to operate at 1066MHz. If your RDRAM isn’t quite up to snuff, simply set the clock multiplier on the memory bus to 3.0. With the system bus at 133MHz and the memory multiplier set to 3.0, this results in a 399MHz (3.0x133) clock speed for your RDRAM.

CPU details

Besides the new bus speed, the 2.26, 2.4B, and 2.53GHz Pentium 4 chips are unchanged from their predecessors. This means that they’re built on Intel’s “Northwood” 0.13-micron core and contain 512K of L2 cache. As far as we know, Intel has no official plans to offer 533MHz chips at slower clock speeds, but this can certainly change. If OEM demand is there, we wouldn’t be surprised to see a 2.0GHz model creep up.

Remember, the Northwood core was originally only available at clock speeds of 2.0A and 2.2GHz. However, Intel went back and also offered 1.6A and 1.8A GHz chips. Quite simply, if the OEM market demands an inexpensive 533MHz P4 (the 2.26GHz Pentium 4 is officially priced at $423), Intel will build it. Intel’s latest specification update sheet hasn’t been updated with the 533MHz chips, so we’re not sure if slower 533MHz chips will be offered at a later date or not.