Dram Installation - Abit PR5 User Manual

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Important Note:
Double-sided Modules
There is an important limitation in us-
ing double-sided SIMM or DIMM mod-
ules. Double-sided modules in one bank
prevents the use of a corresponding
bank of the other type of module. For
example:
• If bank SIMM1/2 has 2-sided mod-
ules installed, you can not use the
DIMM2 socket.
• If bank SIMM3/4 has 2-sided mod-
ules installed, you can not use the
DIMM1 socket.
• If bank DIMM1 has a 2-sided module
installed, you can not use the SIMM3/
4 sockets.
• If bank DIMM2 has a 2-sided module
installed, you can not use the SIMM1/
2 sockets.
Double-sided modules are modules with
memory chips mounted on both sides.

DRAM Installation

The PR5 has numerous possible system memory configu-
rations using the four 72-pin SIMM sockets and the two
168-pin DIMM sockets. The SIMM sockets work in banks
of two to provide a 64-bit data path. SIMM1/SIMM2 are
one bank, SIMM3/SIMM4 are another. The DIMM sock-
ets are each a bank, for a total of four banks. Please note
the following.
• Installed memory is auto-detected by the BIOS
• Minimum installation 2 SIMMs or 1 DIMM mod-
ule for a 64-bit data path
• Fast Page (FP), EDO and SDRAM are all supported,
SDRAM only in DIMM modules
• SIMMs: single or double-sided modules of 4MB and
up supported
• DIMMs: single or double-sided modules of 8MB
and up supported
• DIMM sockets support both 5-volt (FP or EDO)
and 3.3-volt (Unbuffered) DRAM; voltage for both
sockets is set by jumper JP11 (see next page)
• Pairs of SIMMs must be the same memory type,
size and speed but the type and size of a second
pair can be different
• Memory Banks:
SIMM1 & SIMM2
SIMM3 & SIMM4
D I M M 1
D I M M 2
• Bank sequence doesn' t matter, use any combina-
tion as long as other requirements are followed
• DRAM speed must be at least 70ns, can be faster
• Parity checking is not supported
• Maximum 128MB supported
There are numerous allowable memory configurations.
Since bank sequence is not important, as long as you use
SIMMs in pairs you can use any combination of banks.
However, for maximum performance it best to use the
same type of DRAM in all banks installed. SDRAM pro-
vides higher performance than EDO DRAM and EDO is
faster than Fast Page Mode DRAM.