WHAT The Difference in DDR

We did not discuss DRAM and SD RAM also DDR1, and DDR2 because these types of RAMs are in use on PCs and laptops. Only just discuss their some feature to understand DDR3 and DDR4. 1st type of RAM was dynamic RAM then S RAM came means static RAM S RAM synchronize the data with CPU but DRAM does not do this thing. That type of RAM is PC100 means the maximum bandwidth is 800MBs and gets 3.3 voltage. After this next generation is DDR.

I did not want to fall into many mathematical things to bore you but it is necessary to understand you can skip this to chart read the chart below this DDR, DDR1, DDR2, DDR3, DDR4, and DDR5 headings. At last, is how to read the max bandwidth on a RAM when you buy it? See after the chart. Then you can understand the type and speed of RAM.

What is DDR

DDR means Dual Data Rate. Its input-output bus doubles if it is 133MHz transfer 266 MTPS means mega transfer per second. A 133MHz DDR RAM’s maximum bandwidth is 2128 MBPS and gets 2.5 voltages.

DDR2

DDR2 internal bus speed is double that DDR. If DDR1 bus speed is 64bit then DDR2 bus speed is 128bit so its max bandwidth also goes to double its frequency is goes is 533 to 800MHz. If 800Mhz frequency then 6400 with 4 pre-fetch. It gets 1.8 voltage.

DDR3

DD3 internal bus speed is double that of DDR2 which means it runs on 8 pre-fetch. If suppose DDR3 internal clock frequency is 266. the clock frequency 266.6*4 = 1066.6 The data rate is 2133.33 and bandwidth 17000 MBPS. It gets 1.3-1.5 voltage.

DDR4

DD4 internal bus speed is double that of DDR3 which means it runs on 8 pre-fetch. If suppose DDR4 internal clock frequency is 400MHz. If its Data rate is 3200 MTPS Max bandwidth will be 25300. It gets 1.2 voltages.

DDR5

DDR internal bus speed increased the same as above the thing you can technically understand.

SD RAM	3.3 Voltage	100-166 MHz
DDR1	2.5Voltage	266-400MHZ
DDR2	1.8Voltage	533-800MHz
DDR3	1.3-1.5Voltage	1066-1866MHz
DDR4	1.2 Voltage	2133-3600MHz
DDR5	1.1 Voltage	4400-6400MHz

What to see When Buy A RAM?

DDR2 RAM start from PC2-4200 to PC2-8500 if you are buying DDR2 RAM for your PC and laptop you read also bus speed it is also printed after RAM memory PC2-4200U or PC2-5300U like this

DDR3 RAM start from 8500 to 12800 but in laptop rams 2 things are important

Difference between PC3 and PC3l and error of RAM

In many laptops installed PC3 normal RAM but latest models installed with PC3l RAM, it gives error when you install other then made. If a laptop is made by PC3l you use PC3 RAM it gives you a memory error. l means Low voltage RAM. So install PC3l RAM to set this error.