When you pick up a SIMM you'll see a number of chips on either side of a flat board. These chips are called DRAM (Dynamic Random Access Memory). On non-parity SIMM's you'll find eight DRAM chips on one or both sides of the SIMM depending on the size:
A 4MB SIMM has 8 DRAM chips on one side.
An 8MB SIMM has 16 DRAM chips with 8 DRAM chips on each side.
A 16MB SIMM has 8 DRAM chips on one side.
A 32MB SIMM has 16 DRAM chips with 8 DRAM chips on each side.
Both 4MB and 16MB SIMM's look alike because they have 8 chips on one side. Likewise 8MB and 32MB SIMM's look alike because they have 8 chips on each side for a total of 16 chips. You can tell them apart by looking at the DRAM chips themselves.
Each DRAM chip is either 512KB's (1Mx4's ), 2MB's (4Mx4's) or 8MB's (16Mx4). 1Mx4's are used on 4MB and 8MB SIMM's. 4Mx4's are used on 16MB and 32MB SIMM's. 16Mx4's are used in 64MB and 128MB chips. 1Mx4's chips have four sets of five pins and 4Mx4's have four sets of six pins. So for example, you can tell an 8MB SIMM from a 32MB SIMM by counting the pins. The 8MB SIMM will have four sets of 5 pins on each of its chip while the 32MB SIMM will have 6 pins.
16Mx4's are available in a variety of configurations, the most common is a 54-pin TSOP package. 16Mx4's are used in 64MB and 128MB modules. Later this year 32MB (256Mb) chips will be available allowing for 256MB and 512MB modules. By 2001 128MB (1Gb) chips will be available in 1GB and 2GB modules. http://www.oempcworld.com/
No comments:
Post a Comment