1
00:00:00,080 --> 00:00:06,480
every computer needs RAM to function but did you know that pretty much all the

2
00:00:04,160 --> 00:00:09,599
RAM we use these days uses some clever tricks to run much faster than it

3
00:00:08,240 --> 00:00:12,400
otherwise would even older RAM like

4
00:00:11,519 --> 00:00:17,600
this ddr3 i'm holding uses these techniques

5
00:00:15,360 --> 00:00:22,160
in fact it's right in the name ddr stands for double data rate which means

6
00:00:20,320 --> 00:00:26,400
just what it sounds like it means it can move data twice as quickly as single

7
00:00:24,560 --> 00:00:32,079
data rate memory which hasn't been in our computers for very long the original

8
00:00:28,400 --> 00:00:34,079
ddr actually came out way back in 2000

9
00:00:32,079 --> 00:00:38,960
not to be confused with the other ddr which came out in 1998. unfortunately i

10
00:00:36,480 --> 00:00:42,399
don't have a stick of the original ddr to show you but i can show you a bit

11
00:00:40,879 --> 00:00:48,000
about how it works so this is an example of a simple clock

12
00:00:45,280 --> 00:00:53,199
signal that your computer uses to keep components inside synced up

13
00:00:50,399 --> 00:00:59,280
conventionally one piece of data is sent per cycle or for each one of these humps

14
00:00:56,559 --> 00:01:04,559
but you see how each cycle has a rising and a falling edge well ddr sends data

15
00:01:02,079 --> 00:01:08,799
on both the rising and the falling edges which works because your memory modules

16
00:01:06,479 --> 00:01:13,280
can detect at what point the internal clock is in its cycle but hold on a

17
00:01:11,200 --> 00:01:18,240
second this would only be double the data rate over a super old school

18
00:01:15,760 --> 00:01:23,759
single data rate RAM so how are we getting generational improvements like

19
00:01:20,159 --> 00:01:26,080
ddr2 3 and 4 which continue to increase

20
00:01:23,759 --> 00:01:30,479
the data rate by a factor of two each time it turns out that there are

21
00:01:28,320 --> 00:01:34,799
actually two clocks involved in what make ddr RAM work the external bus that

22
00:01:33,360 --> 00:01:40,079
connects your RAM to the rest of the system and an internal memory clock for

23
00:01:37,759 --> 00:01:45,040
ddr2 the internal clock was kept the same but the external bus clock was

24
00:01:42,799 --> 00:01:49,680
doubled this means that the external bus can carry twice as much data per unit of

25
00:01:47,600 --> 00:01:53,840
time to take advantage of this the internal memory array where the data is

26
00:01:51,680 --> 00:01:58,560
actually stored doubles the number of bits sent at one time to the external

27
00:01:56,000 --> 00:02:03,840
memory bus this process is also called prefetching and it's responsible for why

28
00:02:00,640 --> 00:02:06,159
ddr2 is faster than ddr and why ddr3 is

29
00:02:03,840 --> 00:02:10,959
faster than ddr2 the external bus's faster clock can then carry the extra

30
00:02:08,319 --> 00:02:14,879
data and boom you've got faster memory advances in manufacturing that keeps

31
00:02:12,800 --> 00:02:18,800
signal integrity high have allowed newer versions of ddr to operate at these

32
00:02:16,800 --> 00:02:23,680
higher speeds without a hitch it should be noted however that ddr4 works

33
00:02:21,200 --> 00:02:27,360
slightly differently in that memory arrays are divided into bank groups

34
00:02:25,840 --> 00:02:31,360
which means that prefetches can be pulled from different parts of the RAM

35
00:02:29,200 --> 00:02:36,239
at the same time leading to higher speeds than ddr3 boosting the external

36
00:02:33,840 --> 00:02:41,360
clock is also part of how newer versions of ddr can run at faster clock speeds

37
00:02:38,319 --> 00:02:43,360
while drawing less power because the

38
00:02:41,360 --> 00:02:49,120
internal memory array runs at speeds slower than the external bus and sends

39
00:02:46,480 --> 00:02:53,360
more prefetch data per cycle it keeps power requirements from getting too high

40
00:02:51,280 --> 00:02:59,200
which when combined with smaller die sizes means new ddr generations don't

41
00:02:56,080 --> 00:03:01,519
need as much voltage of course unlike

42
00:02:59,200 --> 00:03:06,879
many other generational improvements one thing that newer versions of ddr do not

43
00:03:04,000 --> 00:03:10,800
feature is backwards compatibility this is a stick of current gen ddr4 and

44
00:03:09,120 --> 00:03:16,080
you'll notice that when i hold it up next to this stick of ddr3 that the

45
00:03:13,360 --> 00:03:20,400
notches are in different places that means that these two sticks cannot be

46
00:03:18,239 --> 00:03:23,599
used in the same motherboard it's made this way on purpose since the different

47
00:03:22,000 --> 00:03:28,319
generations of ddr have different electrical and signaling requirements

48
00:03:26,080 --> 00:03:32,640
that or it's just a plot to make all of us buy new memory every couple years

49
00:03:30,720 --> 00:03:37,519
either way i'll cough up whatever they want as long as it has RGB big thanks to MSI

50
00:03:36,000 --> 00:03:43,599
for sponsoring this video check out the MSI vigor gk50 low profile keyboard with

51
00:03:41,760 --> 00:03:47,920
mechanical switches that provide speed precision and endurance it has a high

52
00:03:45,680 --> 00:03:51,360
low keycap design to keep your hands in a comfy natural position and a brushed

53
00:03:49,840 --> 00:03:55,120
metal top plate and matte coating keycaps for durability additional

54
00:03:53,200 --> 00:03:59,439
features include lightning hotkeys to change speed direction and mode a hotkey

55
00:03:57,760 --> 00:04:03,680
for afterburner activation and millions of RGB colors with unique effects and

56
00:04:01,920 --> 00:04:07,920
for a personal touch customize and create your own effects by the MSI

57
00:04:05,760 --> 00:04:11,840
dragon center software learn more today at the links below so thanks for

58
00:04:09,519 --> 00:04:14,560
watching oh thanks for watching guys i'm not gonna do that so thanks for

59
00:04:13,040 --> 00:04:18,079
watching guys if you like this video hit like hit subscribe and hit us up in

60
00:04:16,479 --> 00:04:22,639
the comments section with your suggestions for topics that we should

61
00:04:19,519 --> 00:04:22,639
cover in the future