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TOPIC What types of random access memory (RAM) are used in iMac? DISCUSSION SUMMARY The iMac has two memory expansion slots. To expand the built-in memory (DRAM) in your new iMac, use the following information when ordering memory: DRAM Form Factor - SO-DIMM DRAM Type - SDRAM DRAM Speed - 10 ns (or faster meaning a lower number) Max size of SO-DIMM Supported - 64 MB per slot Total DRAM Supported - 128 MB with both slots filled PowerBook G3 Compatible - No PowerBook G3 Series Compatible - Yes Power Macintosh G3 Compatible - No To expand the video memory (VRAM) in your new iMac, use the following information when ordering VRAM: Form Factor - SO-DIMM RAM Type - SGRAM Power Macintosh G3 Compatible - Yes PowerBook G3 Compatible - Not Applicable PowerBook G3 Series Compatible - Not Applicable Power Macintosh G3 Compatible - Yes MORE DETAILS ON RAM iMac comes with two different types of memory: SDRAM and SGRAM. SDRAM (Synchronous Dynamic Random Access Memory) is the memory that the iMac uses to run Mac OS and applications. SGRAM (Synchronous Graphic Random Access Memory) is the memory iMac uses to display video. Both types of RAM need to be SO-DIMMs. SO-DIMMs are different from the larger DIMMs that have been used in previous Power Macintosh computers. The "SO" stands for "small outline." SO-DIMMs are dimensionally different than standard DIMMs used in other Macintosh desktop computers. So, when you purchase memory, you need to buy SDRAM SO-DIMMs - not extended data output (EDO) RAM or Fast Paged RAM. EDO RAM, a subset of Fast Page RAM, is a type of RAM chip that improves the time to read from memory on faster microprocessors such as the PowerPC. For faster computers, the synchronous dynamic RAM (SDRAM) is recommended. Note: EDO and Fast Paged RAM will not work with the iMac. When purchasing memory for your new iMac, use the following specifications when ordering: DRAM Form Factor - SO-DIMM DRAM Type - SDRAM DRAM Speed - 10 ns (or faster meaning a lower number) Max size of SO-DIMM Supported - 64 MB Total DRAM Supported - 128 MB Note: The RAM for the PowerBook G3 Series is compatible with iMac, however, due to power considerations, iMac specific memory may not work in a PowerBook G3 Series computer. The iMac comes with two SO-DIMM slots on the processor card. Both slots (top and bottom) accept up to 64 MB SO-DIMMs. The bottom slot contains the pre-installed 32 MB SO-DIMM. Remember that additional memory in the bottom slot must be installed by an Apple Authorized Service Provider. The top slot is user-installable. To install memory in this slot, you should refer to the iMac On-line User Guide for memory installation instructions. MORE DETAILS ON VRAM The iMac ships with 2 MB of SGRAM. SGRAM, also used in the Power Macintosh G3 computers, is a faster version of VRAM (Video RAM) used in pre-Power Macintosh G3 computers. You can upgrade to 6 MB of SGRAM by installing the 4 MB SGRAM upgrade. The 4 MB SGRAM upgrade, the only currently available upgrade from Apple, is user installable. However, Apple recommends that an Apple Authorized Service Provider perform the installation. Form Factor - SO-DIMM RAM Type - SGRAM Power Macintosh G3 Compatible - Yes Note: 6 MB of VRAM is required for 3D graphics acceleration at resolutions greater than 640x480 pixels. |