JEDEC Reveals Key Aspects of DDR4
by Kristian Vättö on August 23, 2011 2:01 PM ESTDDR3 made its debut in mid-2007 when Intel released P35 chipset with support for DDR3. Today nearly all desktop, mobile and server platforms support DDR3. iSuppli estimates that DDR3 will account for roughly 90% of DRAM sales this year. However, the next generation DRAM technology is already just around the corner and JEDEC is scheduled to release the full DDR4 specification next year. Yesterday, JEDEC published some of the specifications of the upcoming DDR4 technology.
First and foremost, DDR4 will concentrate on performance and power consumption. The latter is achieved by lowering the voltage to 1.2V, compared to DDR3's 1.5V (although there are DDR3 modules with lower or higher voltage but 1.5V is the standard for most). The performance gain is achieved by increasing the frequency and DDR4 will start from 1600MHz. It's likely that we will see 1866MHz or 2133MHz modules as the standard though, considering that DDR3 went straight for 1066MHz as well, even though a 800MHz specification existed too. The projected maximum speed for DDR4 is 3200MHz but then again, DDR3's maximum is 1600MHz, yet 2133MHz DDR3 modules are available. We will likely see even higher bandwidth DDR4 modules in the future. JEDEC lists the prefetch buffer for DDR4 as 8n, which is identical to DDR3. If this ends up being the case the bulk of the performance increase will be due to higher operating frequencies enabled through more advanced signaling.
The higher operating frequencies come at the expense of some serialization of the interface. The SDRAM memory interface remains one of the last parallel buses in modern PCs. While it doesn't look like DDR4 will change that, we have heard reports of the new memory standard moving to a point-to-point protocol. In other words: one DDR4 module per memory channel. Note that JEDEC hasn't confirmed this will officially make it into the DDR4 spec.
Source: JEDEC
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Andrew.a.cunningham - Tuesday, August 23, 2011 - link
The more bandwidth the better! We're already seeing new IGPs get bottlenecked by 1333 and 1600MHz DDR3 today, and that'll only get worse as time goes on.DanNeely - Tuesday, August 23, 2011 - link
It's not just IGPs. Intel needs one DDR3 memory channel per two cores. Until DDR4 hits mainstream parts are going to be limited to quad core configs.yelped - Tuesday, August 23, 2011 - link
Hopefully, AMD will bundle cheap DDR4 RAM to the OEMs, so laptops with their APUs are not held back.Gauner - Tuesday, August 23, 2011 - link
We still need to see chipsets that support more than 1833 bus, keep in mind that even if you have 3200Mhz memory, if the APU itself cant go any higher than... let's say 2400, it will be mostly useless.And sincerely, I dont se that happening soon, it's expensive to support such high buses and if AMD or intel wanted to do it, they could have done it by now with DDR3 at 2000-2133Mhz.
Kristian Vättö - Tuesday, August 23, 2011 - link
Sooner or later faster buses will be supported. 2133MHz DDR3 didn't come out right after P35, it took years. The same will happen with DDR4. It will take a few years before we will see speeds close to the maximum.Also, there are some reports of 2133MHz support in Ivy Bridge: http://news.softpedia.com/news/Intel-Ivy-Bridge-to...
iwod - Tuesday, August 23, 2011 - link
We either need CPU to have Tri or Quad memory channel without all the MB space ( using Laptop DRAM as standard ? ) or we need a new type of Memory.If every node shrink means doubling of Gfx Power, the life time of memory is suppose to last 2 to 3 node shrink. and if we count 1.5x the bandwidth for doubling the Gfx power, that means we need at least 3x memory bandwidth.
Quad Channel is something CPU maker dont want to go because of the wasted Die Space.
So are we stuck for the next few years starved by memory bandwidth?
Kristian Vättö - Wednesday, August 24, 2011 - link
Memory bandwidth is not the bottleneck. dGPUs have their own VRAM which is often faster than regular RAM. Hence the need for RAM isn't that huge and tests show that faster RAM provides no better performancehttp://www.anandtech.com/show/4503/sandy-bridge-me...
darckhart - Wednesday, August 24, 2011 - link
the speed doesn't even make sense because most ddr3 that claims to hit 1866+ are not at 1.5V. What's the whole point if you have to crank it to 1.65V or higher? especially if you intend on populating all the slots.sangyup81 - Tuesday, August 23, 2011 - link
isn't one module one channel pretty much what unganged mode does anyways?Iketh - Wednesday, August 24, 2011 - link
No, it's each channel running independently from the other so a core doesn't have to share a channel with another core. You're not limited to 2 modules when running unganged, right?.........