Supporting the K6-2 and K6-3 on the ASUS P55T2P4

The ‘Energizer’ Motherboard

The ASUS P/I-P55T2P4 has proven to be almost an engineering miracle in this fast-paced, planned-obsolecence industry. This motherboard was originally released in June 1996, with the famous revision 3.0 being released later the same year. This was one of the first brand-name motherboards to implement the 75MHz bus speed that is now so common. The coverage it received on Tom’s Hardware Guide in November 1996 thrust it into the spotlight, making it one of the most successful motherboards ever sold.

Tom’s Hardware Guide selected the P/I-P55T2P4 as the ‘ultimate overclocking motherboard’ because of it’s speed and stability at 75MHz and 83MHz bus speeds. Even when the Abit IT5H dethroned it, the T2P4 was considered the standard by which ‘overclocking friendly’ motherboards were measured. What is so amazing about this motherboard is that while virtually all of it’s ‘contemporaries’ (including the IT5H) have been all but relegated to the junk heap, the P/I-P55T2P4 can still be used, even with today’s processors (see below for details). Even many motherboards introduced over a year later are considered unusable with the current 2.2v processors.

Supporting Current Processors

Visitors began emailing last summer, asking for details about how to jumper the ASUS P55T2P4 motherboard for the K6-2 (and upcoming K6-3) processors. A little investigation revealed two very nice websites covering this issue: http://www1.jump.net/~lcs/kalle/ and http://www.angelfire.com/bc/upgradecenter/index.html.(Update: neither website is online any more)

Both of these sites not only provide information on the various voltage settings for the last revision, but also have a wealth of other information on upgrading the venerable ‘old’ P55T2P4 motherboard, including how to get 4.0x through 5.5x multipliers! Using a very cool tool called The Processor Protector, we were able to determine all of the possible voltages rev 3.10 boards. This table is provided below (and has been emailed to both of the webmasters of those excellent sites). Note that if your motherboard has a ‘3.2v OK’ sticker on it, the ‘RES’ jumper will be set up to provide approx. 3.2v (measured as 3.17v), otherwise it provides approx. 2.5v (measured as 2.49v). Unfortunately, we did not have the rev. 3.0 board available for testing.

Of course, features such as UDMA and AGP are not supported by the motherboard, however these really provide very little in the way of ‘real world’ performance in any case. Though the motherboard can no longer be considered a truly ‘high performance’ board by today’s standards, it has certainly shown that a properly engineered motherboard does not have to become obsolete in less than a year. With the impending release of the K6-3 400, the performance may actually get close to even the most current Super Socket 7 boards – and it has a larger cacheable memory range to boot!

ASUS P/I P55T2P4 Voltage Settings (rev 3.10)
Pins Jumpered Rev 3.10 3.2 OK
2.5v/2.7v 2.23v 2.23v
2.5v/2.8v 2.29v 2.29v
2.5v/2.9v 2.31v 2.33v
2.5v/Res 2.13v 2.45v
2.7v/2.8v 2.43v 2.45v
2.7v/2.9v 2.45v 2.47v
2.7v/Res 2.23v 2.64v
2.8v/2.9v 2.54v 2.56v
2.8v/Res 2.29v 2.76v
2.9v/Res 2.31v 2.8v
     
2.5v/2.7v/2.8v 2.09v 2.11v
2.5v/2.7v/2.9v 2.11v 2.13v
2.5v/2.7v/Res 1.98v 2.21v
2.5v/2.8v/2.9v 2.15v 2.17v
2.5v/2.8v/Res 2.01v 2.27v
2.5v/2.9v/Res 2.03v 2.29v
2.7v/2.8v/2.9v 2.27v 2.29v
2.7v/2.8v/Res 2.01v 2.41v
2.7v/2.9v/Res 2.11v 2.43v
2.8v/2.9v/Res 2.17v 2.52v
   
2.5v/2.7v/2.8v/2.9v 2.01v 2.01v
2.5/2.7v/2.9v/Res 1.92v 2.11v
2.5v/2.8v/2.9v/Res 1.96v 2.15v
2.7v/2.8v/2.9v/Res 2.01v 2.25v
     
All Jumpers 1.86v 2.01v

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