Editing IBM PC Series 300 (section)

== Memory Topology ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''PC Series 300 memory topology'''
! Generation !! Memory !! Maximum
|-
| 486 / early Pentium (6571 / 6581 / 6585 / 6586) || 4 × 72-pin SIMM, parity || 128 MB
|-
| Transitional (6577 / 6587) || 1 × DIMM-168 ('''5 V EDO only''') + 4 × 72-pin SIMM || 192 MB
|-
| Pentium Pro (6588 / 6589 / 6598) || 4 × 168-pin '''unbuffered 3.3 V EDO DIMM''' 60 ns || 512 MB
|-
| Pentium II / III NLX (6862 / 6892) || 3 × DIMM PC100 SDRAM || 384 MB official / 512 MB unofficial with BIOS update
|-
| Celeron BX (6275 / 6285) || 2 × DIMM PC100 SDRAM, '''non-parity only''' || 256 MB
|-
| Late 300GL (6272 / 6282) || 3 × DIMM PC100 SDRAM || 384–512 MB
|}

'''The DIMM keying notch on the 6577 / 6587 / 6588 boards is for EDO, not SDRAM.''' Physically possible to insert a modern SDRAM DIMM in a 3.3 V EDO slot (won't work, low risk of damage) or to force a 5 V EDO module in a 3.3 V slot (potentially damaging).<ref>https://ancientelectronics.wordpress.com/2021/12/16/ibm-pc-300xl-model-6588/</ref>