Computer Dictionary

Welcome to the Fury-Tech's dictionary of computer related terms and definitions. Find a term in the Table of Contents to view a specific definition, or scroll down to view the entire list of terms.

AGP Aperture Size:

The AGP Aperture Size is the amount of system ram to be shared with the AGP interface. Setting this value too high can steal too much system memory from applications, which can easily offset the benefit of more video RAM. The default setting of 64MB is usually fine, although you can experiment with higher and lower values yourself.

Active Cooling:

Active cooling refers to the use of an active system such as a fan, heatsink/fan combo or watercooling to cool computer components. (See also passive cooling).

Auto Detect DIMM/PCI CLk:

This is another method that can be used to reduce EMI (Electromagnetic Interference). When enabled, it will automatically turn off the clock cycles on unpopulated AGP, PCI or SDRAM slots. Clock cycles on populated slots will also be turned off when not in use if this option is enabled. Since there is no performance hit associated with this option, you can usually leave it on.

Bank Interleave:

Bank interleave allows consecutive data requests to RAM, cycling through each bank of memory. This can give a good performance boost with large RAM modules, since each bank of the module can be accessed consecutively. DRAM chips of 64Mbit or higher have 4 separate internal banks which can be active at the same time. You can set bank interleave to Disable, 2-bank or 4-bank. It is generally recommended that you use the highest setting (4-bank) whenever possible. Bank interleave doesn't usually affect stability as long as the RAM module can support it.

BIOS (Binary Input/Output System):

The BIOS is software built-in to the motherboard. It is responsible for detecting and starting up basic device services in a computer at boot time. The BIOS can also contain a number of user-configurable settings, allowing you to control such things as RAM timings, CPU multiplier, AGP settings, and much more. If you plan on overclocking your computer, you will most likely spend a lot of time changing settings around in your BIOS.

Burst Mode:

This is a generic term, meaning that data is sent faster than normal across a communication line. Burst mode is implemented in many ways across the system bus, PCI bus, and caching methods for the IDE bus.

Bus:

When referring to personal computers, a bus is a collection of wires which are used to transfer data inside a computer system. A bus is made up of two separate buses: the data bus and the address bus. The data bus is used to transfer data from one device to another, and the address bus contains information about where that data should go.

CAS (Column Access Strobe):

A signal which tells the DRAM to accept an address as the column address. Used in conjunction with Row Access Strobe (see RAS) to select a bit of DRAM.

CAS Latency:

CAS latency refers to the ratio between column access time (see Tcac) and clock cycle time. Since column access time refers to the period after the CPU requests a column, to when the data is moved to the output line, a lower CAS latency means less clock cycles to move the data to the output line. It is usually recommended you use the lowest CAS latency which your RAM and motherboard can run stable with.

CMOS (Complementary Metal-Oxide Semiconductor):

The CMOS is a small amount of battery powered memory attached to your motherboard which allows your computer to store things like date and time, so they are not reset every time you turn your computer off. BIOS settings are also stored in the CMOS, and if there is ever a time when your BIOS modifications prevent your computer from booting up, there is usually a clear-CMOS jumper (see jumper) on your motherboard, which will clear the CMOS memory when removed for ~5 seconds.

DOS Flat Mode:

This setting enables DOS mode memory addressing. Windows already uses this method so only enable it if you are using an application that needs it. All memory will be seen as real, instead of as a segment and offset; this can result in better stability where it is needed.

DRAM Command Rate:

DRAM command rate specifies the time to wait after a chip select before activate and read can be started. It is usually recommended you use the lowest command rate that your RAM and motherboard can run stable with. However, at higher frequencies it may be necessary to increase the command rate latency.

DRAM Queue Depth:

DRAM queue depth specifies how deep row refresh requests can be queued. By queueing these requests, they can be issued in burst mode (see burst mode). This way multiple rows can be refreshed consecutively. It is usually recommended you use the highest queue depth which your RAM and motherboard can run stable with.

FSB (Front Side Bus):

Also known as the system bus, and sometimes the memory bus, the front side bus is the primary connection between the CPU and system memory. Other devices in the computer also derive their speeds from the FSB, such as the AGP bus and PCI bus. The AGP and PCI bus generally run at a slower speed than the FSB, and use a divider (see divider) to obtain the correct speed. The CPU also derives its clock speed from the FSB by applying a multiplier (see multiplier). Changing the frequency of the FSB can give you huge overclocks, but since so many components in your computer obtain their speeds from the FSB, it can cause a lot of stress on other components. It's always best to take it one step at a time, so if you are overclocking your FSB then start in small increments. For example, if you normally run at 133MHz FSB, try 134 then test it, 135 then test, 136 then test, and so on.

Heatsink:

A heatsink is a block of metal that is used to help disperse heat from hot running components in your computer. The largest, and generally most important HS in your computer is the CPU heatsink. The CPU is the hottest running part of your computer, and it is important to help transfer heat away from the CPU as quickly as possible. You will also hear the term HSF, which is simply an acronym for HeatSink/Fan - usually referring to the combination of a heatsink and a cooling fan.

Jumper:

A jumper is basically a user controllable circuit. It generally consists of pins which are connected or disconnected using 'shunt', a small plastic coated metal sheath. When closed (shunt is on), the circuit allows electricity to flow through. Jumpers are used for a number of things, and if you look closely at your motherboard you will probably see a few yourself - basically they look like small black plastic rectangles stuck on to two pins. In some cases jumpers are used to change FSB and multiplier settings, or clear the CMOS, or more.

Lapping:

Lapping is the term used to describe the process of smoothing the contact area of a heatsink. Generally this is done by using progressively finer grains of sandpaper to get the smoothest possible surface. This reduces the amount of air in the contact area and increases heat transfer.

Multiplier:

A multiplier is used by the CPU to obtain its clock speed. Since the CPU uses the clock of the FSB, it needs to multiply that clock speed by a number to achieve higher clock speeds itself. The basic formula is FSB x Multi = Clock Speed. For example, a FSB running at 133MHz, coupled with a CPU using a 10.5 multiplier, will result in a CPU running at 1.4GHz (133 x 10.5 = 1,396.5MHz). As you can see, changing either of these variables will result in a higher clock speed, and these are the two major numbers you will be changing if you want to overclock.

Passive Cooling:

Passive cooling refers to the use of a non-mechanical cooling method, such as a heatsink with no fan. Passive refers to the inactive method of cooling, since the cooling method relies on natural heat dissapation through a heatsink. (See also active cooling).

Peltier:

A peltier, or thermoelectric module, is generally a small plate which is mounted between the CPU and HSF. When an electrical current is applied to the peltier, all of the heat in the module is forced to the top, making the bottom very cold. This can be a useful component in moving heat off the CPU. In general terms, a peltier is an array of semiconductor pellets which have been doped so that either negative or positive charge carrier carries most of the current.

RAS (Row Access Strobe):

A signal which tells the DRAM to accept an address as the row address. Used in conjunction with Column Access Strobe (see CAS) to select a bit of DRAM.

Spread Spectrum:

This setting should almost always be disabled. To be CE listed in acceptance with the European market, this setting is included to help reduce EMI (Electromagnetic Interference). It can reduce system performance, so unless you are experiencing serious difficulty with EMI leave this setting off.

Stepping:

Stepping refers to the version of a CPU. Like a software application, version numbers change when bugs are fixed, and updates are made. Unlike software, the stepping of a CPU uses a different format for versioning, usually a proprietary code developed by the manufacturer. Usually the most recent stepping of a processor is the most stable and overclockable, but this isn't always the case. Steppings are helpful when purchasing a CPU you intend to overclock, since doing a little research on the good steppings can help you find the most overclockable chip.

Thermal Compound:

Thermal compound is generally a paste or silver based compound which is applied between a heatsink and the chip being cooled. Thermal compound is important in transferring heat off a chip. Normally the surfaces of the heatsink and chip are imperfect, meaning there are microscopic ridges and bumps on the surface; thermal compound helps to fill these trenches and increase heat transfer into the heatsink.

Tcac (Column Access Time):

Column access time is the time it takes for data to be moved to the ouput line after the CPU makes a column request on the CAS line.

Tras (Active to Precharge):

Tras specifies the amount of time required between an active command to a precharge command. Basically this means the number of cycles that must pass after a bank is opened to when it can be closed. It is usually recommended you use the lowest Tras which your RAM and motherboard can run stable with.

Trcd (Active to CMD):

Trcd, also known as Active to CMD or RAS-to-CAS, is the time we have to wait between a row access request and a column access request. It is usually recommended you use the lowest Trcd which your RAM and motherboard can run stable with.

Trp (Precharge to Active):

The amount of time from a bank precharge request to when it can be activated. It is usually recommended you use the lowest Trp which your RAM and motherboard can run stable with.

Voltage:

The rate at which energy is drawn from an electrical source. This is an important term to be familiar with when overclocking, since an overclocked device will usually require a higher voltage to remain stable. Generally speaking, as the frequency of a chip increases, it requires more voltage to bridge a gap in the unit. Since all silicon has impurities, there will always be gaps. At low clock speeds the current has a chance to go around the gap, but as the clock speed increases the chances of a current not making the jump in time, or at all, increase. Higher voltage will help to sustain a higher clock, but it also increases the heat emitted, and the potential to damage the chip.

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