To simplify matters I have only referred to Intel trade names.. AMD have their own set of marketing terms for CPU features as do other manufactures
CPU = Central Processing Unit - the part of a computer that typically does most of the computational work of a computer. One of the most important parts of a computer.
Cores = For most of the history of CPU's up until the mid 2000's most CPU's consisted of one 'core'. However due to the physics of the materials used to make CPU's it was found that it was not possible to make one core CPU's run faster indefinitely. Also by adding more cores to a CPU different tasks could be run in parallel therefore improving multitasking (where a computer is doing more than one task at a time) and by makes some games and applications run faster if they were suitably coded to take advantage of more cores.
I.e. a first person shooting game where one core was used to run the A.I (artificial intelligence) of the computer players where other cores were used to run the game itself.
The downsides of adding more cores are
1) It makes the die's bigger for the same core design and fabrication method (see nm fabrication process below) and therefore more expensive.
2) A CPU with more of the same type of cores compared to one with less of the same cores will generally not be capable of running as fast.
3) There is a limit to how many cores games and applications can utilise even if they are well coded. Only so much work game be completed in parallel
Threads/ Hyper threading(HT - Intel Only) = Some CPU's are capable of using the under utilised parts of their cores to run more than one set of instructions at a time. Each set of work being done in this fashion is called a 'thread' and Intel calls this technology 'Hyper threading' It allows CPU's to run suitable software more quickly (its similar to adding mores cores to a CPU but an additional core will be superior to an additional thread running on a core).
The combination of cores and threads a CPU has is often abbreviated as Xc/Yt (where c = the number of cores and t = the total number of threads those CPU's can run) i.e. a 6700K is an 4c8t CPU
Die = The ''functional' part of a CPU that contains the circuitry that makes the CPU work. Often used when talking about 'die size' i.e how big (or small) the functional part of a chip is
Wafer = a piece of electronic grade silicon (very high purity) onto which lots of identical Die's are copies using a processes like
photolithograph. Wafer's come in industry standard sizes and so the size of the die's on a wafer affects the total amount of die's that can be produced per wafer
nm = Nano meter - the current size unit used to measure the size of the circuitry on a die. Often referred to as a 'X' nm fabrication process.
i.e Skylake is a range of CPU's made on a 14nm process.
The smaller the size of the process used the smaller a CPU die will be for the same design (Layout).
Yield = Not all the die's on a wafer are the same quality... Some will be faulty and will have to be discarded and some die's may only be party functional or not be capable of running as fast as other Die's using the same voltage. The 'Yield' is used to discuss the amount of functional die's produced from a wafer and the speeds at which the die's can be used at un der a given voltage range.
i.e. Skylake wafers had a poor yield initially
Clock Speed/frequency = the speed at which a CPU runs - normally measured in GHz where 1 GHZ = 1000MHz
1 MHz represents 1 million cycles per second!
i.e - a Skylake 6700K CPU has a base frequency of 4 GHz and a turbo frequency of 4.2GHz
Base/Turbo speed/Frequency (Intel only) = Intel's more recent CPU's don't run constantly at the same speed. They can 'de clock' (lower their frequency) when not doing much. This is normally done to save power used. Conversely they can run faster when requires and this is sometimes referred to as a 'turbo' speed. On CPU's with multiple cores sometimes the turbo speed is determined by how many cores are being used with less cores equating to a higher turbo speed. This allows for software that does not utilise many cores to be run faster whilst still allowing the CPU to run other software that does benefit from more cores (albeit with the individual cores running at a lower speed)
Stock and Overclocked Speed/Frequency = The stock speed is the speed a CPU is rated to run at by the manufacturer by changing the settings on the computer (normally in the BIOS) and by sometimes increasing the voltages used by the CPU a CPU can be run faster than 'stock' speeds and is then said to have been 'overclocked'. This allows the CPU to run instructions more quickly but uses more power, generates more heat and to a degree can shorten the life of the CPU due to gradual
electromigration over time or more sudden failure due to a failure caused by over volting/ overheating of the CPU.
Often abbreviated to 'OC' i.e my CPU is oc'd to 4.5GHz or my CPU can run a 5GHz OC at 1.35volts
Cache (memory) = Modern CPU's have memory built into their die's for short quick storage of information to speed up processes. Intel refers to this memory as L1, L2, L3 and for some CPU's L4 cache in order of decreasing cache speed and increasing cache size for a given set of CPU's. The L1 and L2 cache's are very small - for example the Skylake set of CPU's has: -
L1 cache - 64 KiB per core ,
L2 cache 256 KiB per core,
L3 cache - 8192 KiB (8MB) shared by all cores
(where one KiB (Kibibyte not to be confused with Kilobyte) = 1024 bytes with 1 Bute being made up of eight 'bits' and with each 'bit' representing either a 1 or a 0 in binary)
Intel has added larger '
L4' caches to some recent (and upcoming) CPU's which it has called '
Iris Pro' in sales speak. This memory is primarily intended to speed up the operation of onboard graphics (iGPU) but can assist the CPU in running non graphics related tasks as well - most recently seen on some
'Broadwell' '14nm' CPU's which had 128 MB of eDRAM L4 cache
CPU Socket = The mechanical attachment point on a motherboard where a CPU is placed. Normally CPU sockets are made so that they mechanically wont fit an incompatible CPU but this is not always the case so you need to check your motherboard manual. Intel sockets are named for the amount of pins in the CPU socket (I.e. socket 1366, 1156 etc) - The pins in the socket connect to points on the underside of a CPU linking the motherboard electrically to the motherboard. A CPU socket will include a physical retention system for holding the CPU in place.
Integrated Heat Spreader (IHS) = placed onto of a CPU die to facilitate heat transfer from a CPU to a cooling system and to protect the die from damage. Intel CPU's can either be soldered or use TIM (see below) to join the die to the spreader (Soldered is generally superior)
TIM - Thermal interface material = A paste use to connect different object to assist in the transfer of heat. Commonly used in relation to CPU's between the IHS and the die and between the IHS and CPU cooler
Delidding = The process of removing an IHS with a view to changing the TIM for a better one. **Can cause damage to the die if not performed properly**
IPC - Instructions per cycle/clock =
A measure of how much work a CPU can be done either per cycle (so one of those many millions of cycles per second!) or more commonly used to compare different CPU's with the same clock/frequency. i.e. a 6700K@4GHz is a 4c/8t with higher IPC than a 4c/8t 3770K@4GHz (the Skylake CPU will be quicker despite having the same clock and core/thread count)
