- This is what a
computer that contains
a graphics card computer look like:
- There are actually
2 computer systems inside
a computer that contains
a graphics card:
- An "ordinary" computer consisting
of the CPU that
executes instructions stored
in the RAM (memory)
- An SIMD (vector) computer consisting of the GPU that executes instructions stored in the device memory
- An "ordinary" computer consisting
of the CPU that
executes instructions stored
in the RAM (memory)
- GPU has
different strengths (and weaknesses) than
a CPU:
- GPU is
relatively slower compared
to a CPU
- But a GPU can perform 1000's of (the same) compuations (at a slower pace) at the same time !!!
In summary: the GPU will outperform the CPU if the program performs a lots of computations that use the same operation
Example: the GPU is great to execute these types of code:
for (int i = 0; i < 10000000; i++ ) C[i] = A[i] + B[i];
- GPU is
relatively slower compared
to a CPU
- Image rendering:
- Image rendering algorithms
(see
click here)
use for-loops that
has the above structure
- That's why NVidia and
AMD has develeped
specialized processors to
speed up the
image rendering operations
and sell them as
graphics cards....
- The CPU will "delegate" the image rendering computations tp the GPU "computer"
- Image rendering algorithms
(see
click here)
use for-loops that
has the above structure
- Diagram of the
CPU inter-connection
by NVidia (graphics card producer):
- Difference between
a CPU (= CPU computer) and a
GPU (= GPU computer):
Explanation:
- The CPU fetches
1 instruction and
executes
the instruction on
1 (pair) of input data
- The CPU can execute the instruction very fast
- The GPU fetches
1 instruction and make
multiple ALU units
executes the same instruction
(on different input data)
- The execution time for
1 instruction is
not as fast as
the CPU instruction execution time
- GPU makes up the difference by using multiple simultaneous executions
- The execution time for
1 instruction is
not as fast as
the CPU instruction execution time
- The CPU fetches
1 instruction and
executes
the instruction on
1 (pair) of input data
- The user
interacts with
a computer that
contains a
graphics card (computer)
as follows:
Explanation:
- The user
interacts only with
the CPU computer (= the "traditional" computer)
through the keyboard and
terminal
- The user controls the GPU computer through an Application Programming Interface (API) (= library functions)
- The user
interacts only with
the CPU computer (= the "traditional" computer)
through the keyboard and
terminal