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Buying and Installing SIMMs

SIMMs were widely used when the Intel Pentium was introduced in the early 1990s. They are no longer implemented on new motherboards, but some of the early Pavilion models use SIMMs, including models in the 5xxx, 51xx, 52xx, 53xx, 7xxx, 71xx, 72xx, 73xx, 81xx, and 82xx series.

Some of these systems were shipped with 16 MB of memory, some with 32 MB of memory. SIMMs can be added in various combinations up to the maximum of four 32 MB SIMMs totaling 128 MB of RAM.


Do not install more than 64 MB of memory in motherboards with the 430FX, 430VX or 430TX system controller chipsets as the system will actually run slower due to a memory caching problem. Systems with these chipsets include the 31xx, 32xx series, as well as the 5030, 5040, 5120, 5215, 5250, 5315, 5315D, 5320, 7010, 7020, 7030, 7050, 7070, 7090, 7055, 7110Z, 7125, 7130P, 7145, 7160, 7170, 7222, 7260, 7275, 7310, 8140, 8160, 8201, 8240, 8242, and 8246 models.

The HP motherboards that use SIMMs have four 72-pin SIMM sockets that are arranged in pairs called Bank 0 and Bank 1. Both SIMMs in a bank must have the same type and size of memory installed. SIMMs must be ordered and installed in pairs. You cannot pull one of the SIMMs in an existing pair and replace it with three SIMMs of a higher value. You must keep the existing pair or remove and install two new pairs. Tin lead SIMMs are required. Order 60 ns EDO DRAM (if CPU clock speed is less than 90 MHz, use 70 ns EDO DRAM). The height of the SIMM modules must not exceed 1 inch.

There are no jumper settings required for the memory size or type added. Memory is automatically detected by the system BIOS.

The best expansion is to install four 32 MB SIMM modules, which expands the system to 128 MB (assuming your system doesn't have the 64 MB limit as described earlier). If the system currently has two 8 MB modules (16 MB total), remove them and install four 32 MB modules. If the system currently has 32 MB of memory using two 16 MB SIMMs, you can keep those in place and add two 32 MB SIMMs in the available slots to reach 96 MB of memory, which is adequate for Windows 95. Alternatively, you can remove the existing modules and add four 32 MB SIMMs to reach 128 MB.

If you upgrade one of these early systems to Windows 98, be sure to upgrade to the maximum of 128 MB of memory.

Below are instructions for removing existing SIMMs and installing new, higher capacity SIMMs. Be sure to read through the information about electrostatic discharge in Appendix B.

  1. Turn off the computer and disconnect all of the cables and power cords at the back of the computer.

  2. Open the cover of the case and attach your antistatic wrist strap to the chassis.

  3. Press the holding clips on both sides of the SIMM outward to release it.

  4. Rock the SIMM backward in its slot as shown in Figure 6.3.

  5. Gently pull the SIMM out of the socket and, as you pull it away, note the location of the notch at the base of the SIMM and how it was removed from the slot. You'll need to reinstall SIMMs in the same way.

Now you are ready to install the new SIMMs. Continue with the following steps:

  1. Insert the memory into the socket at a slight backward angle. Make sure the notch on the module matches the notch on the slot. Gently rock the module in the slot to make sure it is seated properly in the slot.

  2. Gently press the SIMM and straighten it to an upward position so that the SIMM snaps into place with the holding clips on both ends of the socket.

  3. Check that the SIMM is securely seated in its slot and that both ends are locked to the socket.

  4. When finished installing the memory, reverse the above procedure to reassemble the computer.

You can obtain more information about these early systems by visiting the following Web pages at the HP Customer Support site:

Memory Installation on HP Pavilion PC Models 7010, 7020, 7030, 7050, 7070, and 7090: http://www.hp.com/cposupport/personal_computing/support_doc/bph01294.html.

HP Pavilion PCs – Memory (SIMM) Specifications for HP Pavilion PCs and How to Upgrade RAM: http://www.hp.com/cposupport/personal_computing/support_doc/bph01828.html.

HP Pavilion PCs – Memory Specifications and Upgrade Capabilities: http://www.hp.com/cposupport/personal_computing/support_doc/bph01091.html.

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