Aptiva 1xx and 3xx System Processor Upgrade

As I have said elsewhere, the1xx and 3xx series Aptivas contain nearly identical components. The different model numbers (121, 172, 372, 392, etc.) usually indicate only differences in processor speed, software preload, included memory, and hard drive size. As a result, changing the processor is a matter of simply removing the old one, installing the new one, and changing some jumpers to let the system know what kind of processor you have installed.

The following is a table of processors and corresponding jumper settings. Thanks to Richard Esposito for providing this information.

Aptiva 1xx/3xx Pentium Processor Settings

CPU Speed External Clock Jumper JP2 Multip. Jumper JP3 Jumper JP25
INTEL 75MHz 50 MHz   1-3, 2-4 1.5 1-3 1-2
INTEL 90MHz 60 MHz   1-3, 4-6 1.5 1-3 1-2
INTEL 100MHz 66.6 MHz   3-5, 4-6 1.5 1-3 1-2
INTEL 120MHz 60 MHz   1-3, 4-6 2 1-3, 2-4 Open
INTEL 133MHz 66.6 MHz   3-5, 4-6 2 1-3, 2-4 Open
INTEL 150MHz 60 MHz   1-3, 4-6 2.5 1-3, 2-4 2-3
INTEL 166MHz 66.6 MHz   3-5, 4-6  2.5 1-3, 2-4 2-3

The following are other Aptiva 1xx and 3xx JP3 settings to consider.

  1. 1-3 for Intel P54C/CT (standard Pentium CPU)
  2. 3-5 for Intel P55C (MMX Pentium CPU) (Refer to Notes below before you act on this.
  3. 1-3-5 Open for Cyrix 6x86 (a.k.a. M1) (Refer to Notes below before you act on this.
  4. Note: JP3 has provision for 3-5, 4-6 (purposes unknown)

The following are Aptiva 1xx and 3xx JP18 and JP19 settings to consider:

  1. 1-2 for Intel Pentium
  2. 2-3 for Cyrix 6x86 (a.k.a. M1)(Refer to Notes below before you act on this.

Click here for a map of Aptiva 1xx and3xx Jumper locations



  1. It may be possible to upgrade an Aptiva 1xx or 3xx with an MMX chip. For notes on this proceedure, check here.
  2. The Aptiva 1xx and 3xx motherboard can be upgraded or overclocked only as high as 166Mhz without an Overdrive processor. This is due to motherboard limitations.
  3. As noted above, the Cyrix processor apparently does not work on the Aptiva 1xx and 3xx motherboard.


E-mail responses

HomeReturn to Index