AMD Details High Bandwidth Memory (HBM) DRAM, Pushes Over 100GB/s Per Stack

MojoKid writes: Recently, a few details of AMD's next-generation Radeon 300-series graphics cards have trickled out. Today, AMD has publicly disclosed new info regarding their High Bandwidth Memory (HBM) technology that will be used on some Radeon 300-series and APU products. Currently, a relatively large number of GDDR5 chips are necessary to offer sufficient capacity and bandwidth for modern GPUs, which means significant PCB real estate is consumed. On-chip integration is not ideal for DRAM because it is not size or cost effective with a logic-optimized GPU or CPU manufacturing process. HBM, however, brings the DRAM as close to possible to the logic die (GPU) as possible. AMD partnered with Hynix and a number of companies to help define the HBM specification and design a new type of memory chip with low power consumption and an ultra-wide bus width, which was eventually adopted by JEDEC 2013. They also develop a DRAM interconnect called an "interposer," along with ASE, Amkor, and UMC. The interposer allows DRAM to be brought into close proximity with the GPU and simplifies communication and clocking. HBM DRAM chips are stacked vertically, and "through-silicon vias" (TSVs) and "bumps" are used to connect one DRAM chip to the next, and then to a logic interface die, and ultimately the interposer. The end result is a single package on which the GPU/SoC and High Bandwidth Memory both reside. 1GB of GDDR5 memory (four 256MB chips), requires roughly 672mm2. Because HBM is vertically stacked, that same 1GB requires only about 35mm2. The bus width on an HBM chip is 1024-bits wide, versus 32-bits on a GDDR5 chip. As a result, the High Bandwidth Memory interface can be clocked much lower but still offer more than 100GB/s for HBM versus 25GB/s with GDDR5. HBM also requires significantly less voltage, which equates to lower power consumption.

Comments

Power savings

[asliarun]

One has to give it to AMD. Despite their stock and sales taking a battering, they have consistently refused to let go of cutting edge innovation. If anything, their CPU team should learn something from their GPU team.

On the topic of HBM, the most exciting thing is the power saving. This would potentially shave off 10-15W from the DRAM chip and possibly more from the overall implementation itself - simply because this is a far simpler and more efficient way for the GPU to address memory.

To quote:
"Macri did say that GDDR5 consumes roughly one watt per 10 GB/s of bandwidth. That would work out to about 32W on a Radeon R9 290X. If HBM delivers on AMD's claims of more than 35 GB/s per watt, then Fiji's 512 GB/s subsystem ought to consume under 15W at peak. A rough savings of 15-17W in memory power is a fine thing, I suppose, but it's still only about five percent of a high-end graphics cards's total power budget. Then again, the power-efficiency numbers Macri provided only include the power used by the DRAMs themselves. The power savings on the GPU from the simpler PHYs and such may be considerable."

http://techreport.com/review/2...

For high end desktop GPUs, this may not be much, but this provides exciting possibilities for gaming laptop GPUs, small formfactor / console formfactor gaming machines (Steam Machine.. sigh), etc. This kind of power savings combined with increased bandwidth cna be a potential game changer. You can finally have a lightweight thin gaming laptop that can still do 1080p resolution at high detail levels for modern games.

I know Razer etc already have some options, but a power efficient laptop GPU from the AMD stable will be a very compelling option for laptop designers. And really, AMD needed something like Fiji - they really have to dig themselves out of their hole.

I think my next card is going to be AMD

[davydagger]

nVidia fanboy since switching to Linux. A combination of them releasing their new unified driver, the latest nvidia chips being notoriously hard for nouveau, and now this, I think my next card is going to come from AMD

Re:Repeated links?

[ArcadeMan]

I hate people who do that...

And please don't forget to register via the links below to get free Bitcoins and Dogecoins so I can get more referrals!

Re:easier solution

[matfud]

No. To drive an external bus requires a lot of silicon space to handle the capacitance resistance and distance. This also requires a lot of power.

Stacked chips required far smaller drivers. The distance is in the mm rather than decimeters. The insulators are far better (as the current and voltage can be far smaller). Capacitance is also far lower. And you do not need to have 1024 bit data paths + address + signaling on the motherboard which makes motherboards far simpler and cheaper to make. Not counting the problems with signal propagation along different length paths on a motherboard (designed into the chip in this case) or having interactions from the multilayer PCB traces.

So yes there are very good reasons to do this.

Re:All of you should buy AMD whenever possible

[drinkypoo]

Typical zealot. I use whatever tool is best for the job, be it AMD or Intel.

History has shown that, like Microsoft, if you give Intel money they will use it for evil. Specifically, it will fund illegal anticompetitive behavior that retards progress in computing.

If you're happy with that, keep giving Intel money. But keep in mind that yes, it really does make you an asshole when you give known assholes money on purpose.