Abit AB-AR5, User Manual

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Installing the Mainboard 2-15
3. Maximum memory capacity 128M Bytes supported by this
mainboard.
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Relationships between memory modules and Pentium
CPUs
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Pentium, 6x86 and AMD-K5 are all 64 bit CPUs, but 72-pin
SIMM modules are only 32-bit. That
’
s why they have to be used
in pairs, because the CPU will always be only able to see 64 bits.
This means that 72-pin SIMM modules have to be installed in
pairs. For instance, SIMM1 and SIMM2 must form a pair, and
SIMM3 and SIMM4 must form another pair. Of course, the two
members of a pair must be of the same kind
¡i
EDO or FP
DRAM
¡j
, and you cannot use pairs from different
“
species
”
.
But the AR5 support different
“
pairs
”
and use different type of
memory modules, notice:
l
¡i
SIMM1 and SIMM2
¡j
must use the same memory
type, as well as
¡i
SIMM3 and SIMM4
¡j
.
l
¡i
SIMM1 and SIMM2
¡j
use the same memory type, and
¡i
SIMM3 and SIMM4
¡j
can use the same type, or a
different type, in order to permit you to obtain the best
speed configuration for each
“
single
”
pair, and to make
the system work at its maximum capacity. If one
memory pair is slower, it will have no influence on the
pair whose speed is higher.
166-pin DIMM modules are 64 bit, so you can use single modules.
On the AR5 mainboard, these modules can support not only EDO
and FR DRAM, but also Synchronous DRAM memory
configurations. The AR5 mainboard does not support SDRAM.
When you install DIMM modules on the mainboard, you don
’
t have to setup
anything, just be sure that you use 3.3V unbuffered 168-pin DIMM modules, and
insert them in the memory socket.
Computer
knowledge