DDR is very rarely noticed term among the masses. We only care about the memory size when we go to a PC store to buy extra RAM stick.
Customer: Hmm.. 4GB must perform better than 8GB!!
Shopkeeper: Yes. Which version do you want DDR3 or DDR4?
Customer: Which is cheaper?
Shopkeeper: DDR3 Sir.
Customer: Get me that one. Any extra of the 4 one.
Shopkeeper: It works at higher frequency.
Customer: No, thanks. My CPU has high frequency to balance.
A very general schematic conversation that goes on in a shop. Shopkeepers sell the DDR3 RAM sticks just to stock them out.
DDR stands for Double Data Rate. The newer the version, the better the performance and less electricity consumption. E.g. DDR3 can transfer 8.5 to 15 GB/s with CPU whereas DDR4 can go upto 21.3 GB/s with more efficiency. You can see DDR4 has high bus clock speed than all it’s older brothers.
You must have noticed that internal rate is the same in all the versions except SDRAM. This is because the DDR has the same internal bandwidth across it’s line up.. SDRAM is smaller in size, thus limited to 166 MHz at max.
Smaller devices like Laptop and Smartphones have similar technology but at a smaller scale. They use LPDDR RAM (LP stands for Low Powered) as they have restricted power supply.
When your system has latest gen. CPU and compatible hardware, always go for the latest highest frequency RAM available within your budget. It will make a difference for sure. Remember, RAM is meant to be the 2nd fastest companion for CPU after cache. The slower the RAM, the slower is your PC.
Along being faster, new gen. RAM stick consumes considerably less power compared to its predecessors.