Dell 486 System Upgrade Options This document will help you identify which system model you have and what upgrade options are available and supported. Dimension/Precision System Identification There are 3 versions of the early 486 Dimension/Precision systems. There are some visual clues that will help you identify which system you have: Revision 1: No PS/2-style mouse port, standard keyboard port (approximately 1/2" diameter connector). Revision 2: PS/2-style mouse port, standard keyboard port Revision 3: PS/2-style mouse port, PS/2-style keyboard port (small, appx 1/4" diameter connector, same on mouse and keyboard) System Memory Upgrades: Model/Revision # slots Memory Description Dell part#'s ----------------------------------------------------------------------------- 486/xx Revision 1 8 1x9, 30pin, parity 25218 - 1MB, 27548 - 4MB 486/xx Revision 2 4 1x36, 72pin, parity 27549 - 4MB, 27875 - 16MB 486/xx Revision 3 4 1x32, 72pin, non-parity 30380 - 4MB, 31066 - 16MB 433P 4 1x36 72pin, parity 25191 - 4MB, 60684 - 16MB 4xx/V, /DV, s/V 4 1x32, 72pin, non-parity 30380 - 4MB, 31066 - 16MB XPS 4xx/V (I & II) 4 1x32, 72pin, non-parity 30380 - 4MB, 31066 - 16MB 4xxi,4xxSi,4xx/P(NP) 2 1x32, 72pin, non-parity 30380 - 4MB, 31066 - 16MB 486/P-xx, 486/D-xx 4 1x36, 72pin, parity 25191 - 4MB, 60684 - 16MB 486/L, /M, /T 4 1x32, 72pin, non-parity 30380 - 4MB, 31066 - 16MB OptiPlex 486/L, /MX 4 1x32, 72pin, non-parity 30380 - 4MB, 31066 - 16MB These memory upgrades are available from Dell Service Parts at 800-372-3355. Processor Upgrades: With the proliferation of Intel Overdrive processors, there are many questions regarding which ones can be used. The Intel DX4 processor has only been validated by Dell on the Omniplex systems. While the DX4/xx may indeed function on other systems, Dell does not recommend the upgrade. The chart below shows the fastest validated processors for each of the systems: Model/Revision Validated Overdrive Processor(s) --------------------------------------------------- 486/xx Revision 1 Intel DX2/xx* 486/xx Revision 2 Intel DX2/xx* 486/xx Revision 3 Intel DX2/xx 433P N/A 4xx/V, /DV, s/V Intel P24T 63mhz Pentium XPS 4xx/V (I & II) Intel P24T 63mhz Pentium 4xxi, 4xxsi, 4xx/P (NP) Intel DX2/xx 486/P-xx, 486/D-xx Intel DX2/xx 486/L, /M, /T Intel P24T 63mhz Pentium OptiPlex 486/L, /MX Intel P24T 63mhz Pentium *Speed can not be changed (i.e. 25Mhz system uses DX2/50, 33Mhz system uses DX2/66) These processor upgrades are available from DellWare at 800-449-3355, or from local retail outlets. HARD DRIVE UPGRADES: IDE hard drives are getting very inexpensive. New large drives (over 528mb) are widely available but won't work in most 486 systems without certain modifications. The following systems will support EIDE (or LBA) drives without modifications: Model/Revision Notes XPS 4xx/V Revision II: The Revision II system has TWO IDE connectors on the system board. The Revision I system only has ONE connector and requires the same modifications as other system types. OptiPlex 4xx/Le/Me/MTe: Only one IDE connector, but has support for EIDE drives Dimension 4xx/DL/DM/DMT: Only one IDE connector, but has support for EIDE drives All other systems will require ONE of the following modifications to utilize disk space above 528mb: Use of disk overlay software. This software is normally provided by the drive manufacturer. This is certainly the easiest method to use, but can cause compatibility problems with some operating systems (OS/2 and Windows NT) and will cause a slight degredation in performace. Installation of an EIDE controller card with BIOS translation for LBA mode drives. This is the best way to go for maximum compatibility and reliability. These cards can be purchased from Dellware (or other retail outlets) for prices ranging from $40 to $150. Three possible cards are listed below: GSI Model 18: Allows for two EIDE devices (hard drive or CD-ROM). Available from Dellware as item # 33637-52. GSI Model 21: Allows for two EIDE devices, 4 diskette drives and can double the speed of QIC-80 tape backup drives. Dellware item # 33655-52. GSI Model 32: Allows for two EIDE devices, 4 diskette drives, high speed QIC-80 tape interface, and 16550 UART serial I/O. This might be a good card if you plan on using a 28.8 external modem in an older system that does not have 16550 UARTs. Dellware item # 56372-52. If you do not find your system listed, or have further questions, please feel free to contact Dell for more assistance.