Upgrading Dram Memory; Memory Upgrade Options - DEC AlphaPC 164 User Manual

5.2 Upgrading DRAM Memory

There are three options for upgrading DRAM memory (Table 23).
Table 23 Memory Upgrade Options
Memory Bus
Option Width Before
1 128-bit
2 128-bit
3 256-bit
To widen the memory bus to its 256-bit maximum (upgrade option 2), add four
SIMMs and make a jumper change (remove J1). The SIMMs that you add must be of
the same size (nMb
SIMMs already in the system. Refer to Figure 1 for SIMM connector and jumper
location.
1. Observe antistatic precautions. Handle SIMMs only at the edges to prevent
damage.
2. Remove power from the system.
3. Hold the SIMM at an angle with the notch facing the key in the socket.
4. Firmly push the module into the connector and stand the module upright. Ensure
that the SIMM snaps into the metal locking clips on both ends.
5. For 128-bit memory bus width, jumper J1 must be in. For 256-bit memory bus
width, jumper J1 must be out.
6. Restore power to the system.
Configuring and Upgrading DRAM Memory
20
Memory Bus
Width After Upgrade Possibilities
128-bit Replace the 4 SIMMs in sockets J5 through J8
with SIMMs of greater size, thus retaining the
128-bit memory bus width.
256-bit Add 4 SIMMs in sockets J9 through J12 with
sizes equal to those in sockets J5 through J8,
thus widening the memory bus width to 256
bits.
256-bit Replace the 8 SIMMs in sockets J5 through
J12 with SIMMs of greater size.
36-bit) and have an access time equal to or less than the four
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