Ask the Experts: DDR5 MRDIMMs — Transcript

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1. 0:02[Music]
2. 0:12welcome everyone Tas the experts I'm Tim
3. 0:15messy and I am joined today by my memory
4. 0:18expert John ebley who is the vice
5. 0:20president of product marketing for our
6. 0:21memory interface chips at rambus today
7. 0:24we're going to be talking about
8. 0:26mrdm hello
9. 0:28everyone Thanks for joining John so why
10. 0:31don't we kick it off with what is mrdm
11. 0:34and what are the benefits uh so Tim mrdm
12. 0:37is a new ddr5 memory module architecture
13. 0:41uh that reuses a lineon share of the
14. 0:43existing ddr5 infrastructure uh in use
15. 0:47now uh but it does introduce a few new
16. 0:50important Concepts that can provide huge
17. 0:52memory bandwidth and capacity
18. 0:56benefits uh start starting on the
19. 0:58bandwidth front uh and Mr dim utilizes
20. 1:02standard ddr5 dram devices uh in a
21. 1:05configuration that doesn't look uh too
22. 1:07different from an R
23. 1:09dim uh but what it does is that pairs of
24. 1:13or ranks of Damm are simultaneously
25. 1:17activated and accessed in parallel and
26. 1:20these data streams are then multiplexed
27. 1:22together onto signals running twice the
28. 1:26native Dam
29. 1:27speed uh so the number of signals
30. 1:29between between the module and the CPU
31. 1:31that's all the same no change in the
32. 1:34standard dim connector but uh the data
33. 1:37rate per signal and the bandwidth
34. 1:39available to the CPU per dim slot has
35. 1:43effectively
36. 1:44doubled uh the parallel access of these
37. 1:47dams and the mxing and demuxing of these
38. 1:50parallel accesses leads to the effective
39. 1:54bandwidth increase which can now scale
40. 1:56Beyond uh the native Dam speed
41. 2:00so uh as an
42. 2:02example um we could have an mrdm that
43. 2:05uses standard ddr5 6400 devices and that
44. 2:10new module would have an equivalent
45. 2:13bandwidth uh to an RM that utilizes ddr5
46. 2:1812,800 megatrans for per second
47. 2:22dams now moving to the the capacity
48. 2:25front uh the change in protocol to
49. 2:28address ranks and parallel and the
50. 2:31physical changes on the module now allow
51. 2:34for more than two ranks of drams to be
52. 2:38addressed uh today as R dims and
53. 2:41standard rcds are defined uh there's not
54. 2:44a coste effective way to go beyond two
55. 2:47ranks of
56. 2:48dams uh with these Mr dim
57. 2:51changes um we can have a taller dim with
58. 2:56four to eight ranks of single die
59. 2:58package Dam or we could have a standard
60. 3:01size uh dim with four to eight ranks of
61. 3:04dual die packages and this is a very
62. 3:07cost-efficient way of increasing the
63. 3:10capacity for slot in a ddr5
64. 3:14system in order to reap these benefits a
65. 3:17CPU must explicitly support mrdm to take
66. 3:21advantage of these features and we
67. 3:24expect most server CPUs will in the
68. 3:26future support mrdm
69. 3:30so John you mentioned bandwidth and
70. 3:32capacity and I know in discussions we've
71. 3:35had in uh previous episodes we talked
72. 3:38about how for ddr5 rdms brand new
73. 3:42chipset really to get the bandwidth and
74. 3:44capacity benefits are we looking at a
75. 3:47new chipset required for ddr5 Mr DM a
76. 3:52good question Tim and the answer is
77. 3:54mostly yes um beyond the CPU support I
78. 3:58just mentioned uh there are new and
79. 4:00upgraded components on the module
80. 4:03necessary to achieve the functionality
81. 4:06and benefits that I was just talking
82. 4:07about it um not everything changes The
83. 4:10Damp components are
84. 4:12unchanged uh the SPD and thermal sensor
85. 4:16are the same ones used on RM today so
86. 4:19that technology is directly
87. 4:21leveraged uh the two key new components
88. 4:25are the multiplexing registered clock
89. 4:27driver or MRC CD and the multiplexing
90. 4:32data buffer or
91. 4:34MDB uh so let me start with the the MDB
92. 4:37uh because it interfaces to the two
93. 4:40ranks of of dam I mentioned before and
94. 4:43it does the multiplexing and D
95. 4:46multiplexing necessary to convert a
96. 4:4916bit interface running at Native Dam
97. 4:52speeds to an 8bit interface running at
98. 4:56twice that
99. 4:57speed furthermore it provides load
100. 5:00isolation to the CPU which is a key
101. 5:03enabler for mrdm to increase the number
102. 5:06of ranks and overall capacity of the
103. 5:10module uh these mdbs are located very
104. 5:13close to the goldfingers of the dim for
105. 5:17Superior signal integrity and there are
106. 5:1910 such devices on the module to provide
107. 5:22the full 80 bit host ddr5
108. 5:28interface so in order to get full
109. 5:31utilization of this bandwidth the
110. 5:33command bandwidth to these parallel
111. 5:36ranks must be
112. 5:37maintained the mrcd extend extends the
113. 5:41typical rcd function to receive an
114. 5:44inleaf stream of dam commands at twice
115. 5:48the typical R dim rate it then D
116. 5:52interleaves the data stream and then
117. 5:54steers it correctly to its rank specific
118. 5:58outputs furthermore it now communicates
119. 6:00with the mdbs to configure them properly
120. 6:04for read and write burst
121. 6:07operations U and there's one more
122. 6:09component I should mention uh you know
123. 6:12given the parallel activations of dam
124. 6:14ranks and the additional chips on the
125. 6:17module uh that have been added to the
126. 6:19chipset for these features the absolute
127. 6:22power envelope of the module is higher
128. 6:24than a typical RM uh therefore a new pic
129. 6:28the pic 503
130. 6:30has been defined to comfortably handle
131. 6:32this amount of power required of such a
132. 6:35high bandwidth high capacity dim John
133. 6:39you mentioned the pic 5030 now earlier
134. 6:41this year your team introduced a family
135. 6:45of pimix 5000 5010 5020 and 5020 was
136. 6:50kind of this new flagship the extreme
137. 6:52current pic how does the pic 5030 compar
138. 6:55to the compared to that family you've
139. 6:57introduced
140. 7:01right right so as we go to these higher
141. 7:03speeds higher capacities with higher
142. 7:07support chip content on the module um
143. 7:10these first generation of server pmix
144. 7:12are starting to run out of steam with
145. 7:14regards to their current output at high
146. 7:17efficiency um the pic 5030 has been
147. 7:21defined to support all dims through the
148. 7:24end of life of
149. 7:25ddr5 so it'll be used on mrdm like I was
150. 7:29talking about that runs at you know
151. 7:3112,800 megat transfers per second um and
152. 7:35it will also be used to support our dims
153. 7:39running at 8,000 megat transfers per
154. 7:41second and higher um so we'll we'll kind
155. 7:44of take these different variants of the
156. 7:46Gen one pmix server and have a single
157. 7:49Gen 2 pmix server uh pic um now if we
158. 7:54look at from a component perspective how
159. 7:55does the 5030 compare to say a 5020
160. 8:00um I'll kind of talk about three key
161. 8:01changes uh one is the addition of two
162. 8:05output switching Regulators to bring the
163. 8:07total to six so we're going to four to
164. 8:10six uh each of those six outputs can
165. 8:13sustain a DC current of anywhere from
166. 8:16five up to seven and a half amps uh so
167. 8:19it can source and provide a lot of
168. 8:21current uh from the nominal 12vt input
169. 8:25okay um you know so we have an increased
170. 8:27number of regulators also how we
171. 8:30configure those Regulators are more
172. 8:32flexible in the 5030 um so they can be
173. 8:36configured into sign single uh dual and
174. 8:40three-phase
175. 8:41Regulators um the three-phase regulation
176. 8:44is new in 530 and this flexibility
177. 8:47allows for maximum efficiency for each
178. 8:51particular dim
179. 8:53type and speaking of that um pic 530
180. 8:57being used on both our GMS and Mr dims
181. 9:01when uh when an enduser buys their
182. 9:04servers do they have to decide at that
183. 9:07time hey I'm going to use just Mr dims
184. 9:10or I'm going to use just RDM 8000 on
185. 9:13this particular
186. 9:15configuration you know one of the nice
187. 9:17things about this technology is that it
188. 9:20can be a drop in
189. 9:21replacement uh a single motherboard
190. 9:24designed will support both mrdm and RDM
191. 9:29and the dim connector is the same and
192. 9:32the routing
193. 9:33topology the physical eray the protocol
194. 9:35erer uh is the same from the host to the
195. 9:39dim so a user does not need to decide
196. 9:42when designing their servers or even
197. 9:45when initially deploying the server as
198. 9:47they can always come back and upgrade at
199. 9:49a later time uh this provides a lot of
200. 9:52flexibility through the life cycle of
201. 9:54the
202. 9:56server great so John um when can we
203. 9:59expect to see servers uh in the market
204. 10:02that use mrdm 12800 and is there a road
205. 10:05map uh beyond that
206. 10:08point we expect servers that would
207. 10:11utilize mrdm
208. 10:1412800 uh to be launching and in volume
209. 10:17in
210. 10:192026 um and um you know we do Envision
211. 10:22that similar to R dims which have had
212. 10:25many ddr5 speed bins uh based on the
213. 10:28native speed of the D
214. 10:30devices uh that Mr dim and the chipset
215. 10:34that enables it it will also be
216. 10:37multigenerational um these future
217. 10:39roadmap modules Beyond
218. 10:4212800 uh will leverage faster underlying
219. 10:45dams and signaling Innovations in the
220. 10:48host and our logic chipset to reach
221. 10:51these even higher speeds and
222. 10:53capacity John as a final question why
223. 10:57should customers uh choose rambus memory
224. 11:00interface
225. 11:03chips thank you for that question uh
226. 11:06rambus has been a trusted us-based
227. 11:08partner and innovator in the memory and
228. 11:11Signal Integrity space now for over 30
229. 11:15years uh and over the last 10 of those
230. 11:17years uh We've really established
231. 11:19ourselves as a robust supplier of high
232. 11:23quality semiconductor products that meet
233. 11:26the market windows for our customers uh
234. 11:29with the performance and margin that
235. 11:31exceed the
236. 11:33specifications rambus is a complete
237. 11:36supplier of components for memory
238. 11:37modules
239. 11:38today uh we have the necessary memory
240. 11:41subsystem experience to develop fully
241. 11:45interoperable products and we have the
242. 11:47tools and the core competency uh to
243. 11:51quickly help our customers with bring up
244. 11:53enable and
245. 11:55qualification of their products in their
246. 11:58end use case
247. 12:00environments wonderful John thank you so
248. 12:02much for your time today and thank you
249. 12:04everybody for joining us we'll see you
250. 12:07here again real soon on ask the
251. 12:10experts it's always a pleasure spending
252. 12:12time with you Tim thank you and thank
253. 12:14you for everyone goodbye thank you Gian
254. 12:25[Music]