PC30 Ch5 Memory+Processors Glossary

A method of measuring access timing to memory, which is the number of clock cycles required to write or read a column of data off a memory module. CAS stands for Column Access Strobe. Compare to RAS Latency.

See Double Data Rate SDRAM.

(dual inline memory module) A miniature circuit board installed on a motherboard to hold memory. DIMMs can hold up to 16 GB of RAM on a single module.

Double Data Rate SDRAM (DDR SDRAM) A type of memory technology used on DIMMs that runs at twice the speed of the system clock. Also called DDR SDRAM, SDRAM II, and DDR.

A DIMM feature whereby memory chips are installed on both sides of a DIMM.

A motherboard feature that improves memory performance by providing two 64-bit channels between memory and the chipset. DDR, DDR2, and DDR3 DIMMs can use dual channels.

Two processor sockets on a server motherboard.

Double-sided DIMMs that provide two 64-bit banks. The memory controller accesses first one bank and then the other. Dual-ranked DIMMs do not perform as well as single-ranked DIMMs.

dynamic RAM (DRAM) The most common type of system memory, it requires refreshing every few milliseconds.

(error-correcting code) A chipset feature on a motherboard that checks the integrity of data stored on DIMMs or RIMMs and can correct single-bit errors in a byte. More advanced ECC schemas can detect, but not correct, double-bit errors in a byte.

graphics processing unit (GPU) A processor that manipulates graphic data to form the images on a monitor screen. A GPU can be embedded on a video card or on the motherboard or integrated within the processor.

The Intel technology that allows each logical processor within the processor package to handle an individual thread in parallel with other threads being handled by other processors within the package. (HyperTransport- The AMD technology)

The AMD technology that allows each logical processor within the processor package to handle an individual thread in parallel with other threads being handled by other processors within the package. (Hyper-Threading -The Intel technology)

Level 1 cache (L1 cache) Memory on the processor die used as a cache to improve processor performance.

 Level 2 cache (L2 cache) Memory in the processor package but not on the processor die. The memory is used as a cache or buffer to improve processor performance. Also see Level 1 (L1) cache.

 Level 3 cache (L3 cache) Cache memory further from the processor core than Level 2 cache, but still in the processor package.

The memory a processor addresses at one time. Today’s desktop and notebook processors use a memory bank that is 64 bits wide.

A processor technology whereby the processor housing contains two or more processor cores that operate at the same frequency but independently of each other.

The factor by which the bus speed or frequency is multiplied to get the CPU clock speed.

Two processing units installed within a single processor and first used by the Pentium processor.

A system that contains more than one processor. The motherboard has more than one processor socket and the processors must be rated to work in this multiprocessor environment.

The frequency at which the CPU operates. Usually expressed in GHz.

Technology used by a motherboard and DIMMs that allows the memory controller to access four DIMMS at the same time.

A method of measuring access timing to memory, which is the number of clock cycles required to write or read a row of data off a memory module. RAS stands for Row Access Strobe. Compare to CAS Latency.

See Double Data Rate SDRAM.

The memory controller on a motherboard that can access only one DIMM at a time. Compare to dual channel and triple channel.

A DIMM that has memory chips installed on one side of the module.

(small outline DIMM) A type of memory module used in notebook computers that uses DIMM technology. A DDR3 SO-DIMM has 204 pins. A DDR2 or DDR SO-DIMM has 200 pins. Older, outdated SO-DIMMs can have 72 pins or 144 pins.

static RAM (SRAM) RAM chips that retain information without the need for refreshing, as long as the computer’s power is on. They are more expensive than traditional DRAM.

Each process that the CPU is aware of; a single task that is part of a longer task or program.

When the memory controller accesses three DIMMs at the same time. DDR3 DIMMs support triple channeling.

An older processor that first used the number 86 in the model number and processes 32 bits at a time.

Hybrid processors that can process 32 bits or 64 bits.