https://youtu.be/3lv1TxUXIbo?t=651
If gddr5 vram is suitable as system memory yet performs better on general PC productivity tasks, why does normal standard ddr rams even exists ?
Because of difference in manufacturing costs ? Or, something else ?
https://youtu.be/3lv1TxUXIbo?t=651
If gddr5 vram is suitable as system memory yet performs better on general PC productivity tasks, why does normal standard ddr rams even exists ?
Because of difference in manufacturing costs ? Or, something else ?
First the car analogy. Cars are faster than buses for individual journeys (lower latency). However, if you want to move 50 people from from A to B the bus is more efficient. (higher bandwidth). If you want to move 50 people, each to different locations across the city is a much more complex task. A small fleet of taxis will be more efficient.
GPUs achieve efficient graphic processing by doing the same computation many times in parallel on large amounts of data and benefit from GDDR5 which has higher bandwidth. CPU tasks are less predictable, generally accessing small amounts of data from different memory locations. DDR4 has lower latency as it is optimised for CPUs. Also modern CPUs have very large RAM caches compared to GPUs.
Cost: GDDR5 is of the order of 10x the cost per Gb of DDR4.
The Chinese console in the video appears to be using an AMD APU (CPU and GPU units on the same chip). That chip is designed to have a single set of memory for both the CPU and GPU units.
Since it's primary a games machine rather than a general purpose computer, the Chinese console designers have probably chosen to optimise graphics performance by using GDDR5 even though it costs more.
Note that Xbox Ones and PS4s also use AMD APUs. The original Xbox One used DDR3 RAM. The PS4 and Xbox One S uses GDDR5.