RAM Flashcards
RAM Sticks and Speeds
RAM has two features: Capacity and Speed.
RAM is dependent on the speed of your motherboard.
DIMM means Dual In-Line Memory Module. The opposing pins have a different job.
(DRAM) Dynamic Ram was the first type of RAM used in computers and is still used today. Every bit of RAM is stored with a little capacitor and a little transistor.
(SDRAM) Synchronus DRAM : Has a 168 Pin DIMM, it has two notches in it. This RAM is synchronized to the system clock. It used a PC rating from the mother board to match up its clock speed with the mother board.
(DDR SDRAM) Double data rate SDRAM : Has 184 DIMM package. DDR has a single notch. It doubles the motherboard speed. (Motherboard x 2) = DDR Speed. Take the DDR speed and multiply it by 8 = your PC number. Math example:
100 MHZ Motherboard
Motherboard * 2 = 200
DDR 200 * 8 = PC 1600
(DDR2) : Has a 240 pin DIMM and the notch is in a slightly different place than DDR SDRAM. DDR2 doubles the motherboard speed which gives you your DDR speed but then it also has a clock doubling feature which doubles your DDR speed and then you multiply that by 8 which equals your PC2 speed. Math Example:
100 MHZ Motherboard
Motherboard * 2 = 200
DDR2 400 * 8 = PC2 3200
(DDR3): Has a 240 pin DIMM and the notch is in a slightly different place than (DDR2). It quadruples the speed of the bus. Example of the math would be: 100 MHZ Motherboard Motherboard x 4 = 400 400 * 2 = DDR3 800 DDR3 800 x 8 = PC3 6400 speed
RAM Capacity
RAM is additive meaning that all of your RAM sticks are added up.
Your motherboard determines the capacity of RAM that can be installed.
Avoid mixing RAM sizes and speeds as it can cause stability issues.
Other Types of RAM
RAMBUS RAM : It was the first double pumped RAM. It has two notches and a 184 pin RIMM. It had to be installed in twos. Any leftover slots needed a CRIMM installed. So if you had a RAMBUS motherboard, every RAM slot would be populated with either RAM or CRIMM for the absence of RAM.
Double-Sided RAM has memory chips on both sides of the RAM. Your motherboard has to support this.
ECC and Parity RAM : RAM that has extra chips that are designed for error correction and increase stability. This is usually used within big server systems and your motherboard has to support this.
(SODIMM) Small outline DIMM: Created for laptops. They have the same speeds and capacities as desktop RAM. It has to be the correct pin sizing for your laptop.
Traditional sizes are 100, 144, and 200 pin. 204 Pin (SODIMM) is always (DDR3).
Installing RAM
Research your motherboard specs.
Most DD RAM is Dual, Triple, and Quad Channeled to where you have to put in either 2 or 4 sticks.
Every stick in a channel has to be the same speed and capacity.
When installing a stick you do not touch the pins or the memory chips.
Troubleshooting RAM
Use the system applet to check how much RAM windows can see on your system.
CPU-Z to detect your RAM
SPD is a RAM feature called Serial Presence Detect it will show you the open slots and the type of existing RAM.
Memtest86 tests your memory. It takes hours to run. You have to boot into Memtest86.
Windows 7 and later has a memory test diagnostic.
These tools won’t tell you which stick is bad.
