User Guide

Hardware Installation
2-29
II. Speed: normally marked as as -12, which means the clock cycle time is
12ns and maximum clock of this SDRAM is 83MHz. Sometimes you can
also find the SDRAM marked as -67, which means maximum clock is
67MHz.
III. Buffered and non-buffered: This motherboard supports non-buffered
DIMMs. You can identify non-buffered DIMMs and buffered DIMMs
according to the position of the notch, following figure is for your reference:
buffered
non-buffered
Reserved
Because the positions are different, only non-buffered DIMMs can be
inserted into the DIMM sockets on this motherboard. Although most of
DIMMs on current market are non-buffered, we still recommand you to ask
your dealer for the correct type.
IV. 2-clock and 4-clock signals: Although both of 2-clock and 4-clock signals
are supported by AP5VM, we strongly recommand you to choose 4-clock
SDRAM in consideration of reliability.
Tip: To identify 2-clock and 4-clock SDRAM, you
may check if there are traces connected to
golden finger pin 79 and pin 163 of the SDRAM. If
there are traces, the SDRAM is probably 4-clock;
Otherewise, it is 2-clock.
V. Parity: This motherboard supports standard 64 bit wide (without parity)
SDRAM.
Because Pentium processor has 64 bit bus width, the four SIMM sockets are
arranged in two banks of two sockets each, they are Bank0 and Bank1. Both
SIMMs in each bank must be in the same size and type. It is allowed to have
different speed and type in different bank, for example, 70ns FPM in one bank
and 60ns EDO in another bank, in such case, each bank is independently
optimized for maximum performance. The memory timing requires at least
70ns fast page mode DRAM chip, but for optimum performance, 60ns EDO
DRAM is recommended.