For the original document, go to Dr Jim's P70 Project
      The P70 came in two planar versions: the older 38F4688/65X1564, used primarily in the 20 MHz -061 machines (but also seen in some -121 20 MHz boxes), and the 38F6973/56F9085 used in 16 MHz and 20 MHz -121 models. 
   The 38F4688/65X1564 planars have the 386DX socket immediatly to the right of the 387DX coprocesssor socket, and two BIOS ROMs near the upper edge of the board.  The 38F6973/56F9085 has the 386DX socket above and to the left of the 387DX socket.  Another distinguishing feature of the newer models is the inclusion of video output filtering on the video card instead of on a 'daughter card' fitted in series with the video output cable.  The newer planar seems slightly  faster on some benchmarks, but the difference is hardly noteworthy.

GRAPHICS
The VGA port supports all VGA graphics and text modes including 640 x 480 graphics, 320 x 200 graphics in 256 colors, and 720 x 400 text using any optional PS/2 VGA color display, and maintains compatibility with CGA and EGA modes.

       Additional features of the system unit include:
o   One general purpose 32-bit full-length Micro Channel slot*
o   Half-length Micro Channel slot that can be used for products such as the PS/2 300/1200/2400 Internal Modem/A (#1755)
o   85-watt automatic voltage-sensing power supply
o   Time and date clock with battery backup
o   Integrated 16-grayscale plasma display, and an integrated version of the IBM Enhanced Personal Computer Keyboard.
*  Some half-length cards that fit in a half-length slot may not fit in a full-length slot.
 

       The Token-Ring Network PS/2 (R) Model P70 386 Adapter/A (#1598) permits attachment of the Personal System/2 (R) Model P70 386 (8573-061 and 8573-121) to the IBM Token-Ring Network.  This adapter is half-length and designed to fit in the short slot.  It transmits and receives at four million bits per second using protocols conforming to IEEE 802.5 and ECMA 89 standards.  The adapter provides logical link control functions conforming with the IEEE 802.2
standard and is compatible with International Standard ISO-8802/5. It provides 16KB of random access memory (RAM) and all of the function of the IBM Token-Ring Network Adapter/A (#4790).  To facilitate attachment to the IBM Personal System/2 P70 386, a unique L angle connector with a permanently attached short cable is provided.

8573-031 30 MB Hard Disk, 16 MHz planar
8573-061 60 MB Hard Disk, 20 MHz planar
8573-121 120 MB Hard Disk, 20 MHz 

The PS/2 160MB Hard Disk Drive upgrade (#4889) for Models 8550Z and 8570 is not supported on the PS/2 8570-E61 serial number ranges 1500000 -- 1999999, 2500000 -- 2515999, 7000000 -- 7163999, and F000000 -- F000999.  Also, feature number 4889 is not supported on the PS/2 8570-U61 serial number range U000001 -- U001476.