Studied by 13 people
What is clock speed?
everything in the CPU is coordinated by the pulse of an internal clock
The number of FDE cycles run per given
time/second
measure of how quickly a cpu can process instructions
the default clock speed is 3.5GHz meaning it can process 3.5 billion instructions per second
How does clock speed affect CPU performance?
the faster the clock speed, the more FDE cycles are completed so more instructions are processed per second and a better performance
overclocking - increasing the clock speed higher than the recommended rate. leads to faster performance but also overheating and damage to the machine
underclocking - decreasing the clock speed lower than the recommended rate. leads to slower performance but will increase the lifespan of the machine.
What is a core?
a complete set of CPU components and each can perform its own FDE cycle
multicore CPU has more than one of the same components in the CPU
How does the processor speed and number of cores affect CPU performance?
one cycle per second = 1Hz = 1 instruction per second
CPU can only execute 1 instruction at a time
in theory, a dual core processor has the potential to execute 2 instructions at a time and a quad can do 4
however this is only under ideal conditions such as a program that has been designed to work with multi core processors
if one core is waiting for another core to finish processing or the software used is not written to make use of multi cores, the performance may not increase
What is cache memory?
small amounts off very fast and expensive memory in the CPU
used for frequently and recently accessed data
How does cache memory affect CPU performance?
faser to access as it is closer to the CPU than RAM so it can provide data and instructions at a faster rate
useful if there is a while loop in a program - storing all the instructions in cache speeds up execution
computer with more cache has a faster performance - repeatedly used instructions can be accessed quicker
costly so most computers only have a small amount
in most systems, level 1 is used 50% of the time and level 2 is used 90% of the time - reduces the time the CPU has to wait
What are the features of level 1 cache?
extremely fast but small
2-256KB
located on the CPU
each core will have its own level 1 cache
What are the features of level 2 cache?
very fast but slower and bigger than level 1
256KB-8MB
located on the CPU
usually also given to each core
What are the features of level 3 cache?
slowest and biggest cache but still faster and smaller than RAM
4MB-50MB
located on CPU and shared between all cores on the processor.
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