Intel Broadwell Architecture Preview: A Glimpse into Core M
by Ryan Smith on August 11, 2014 12:01 PM ESTPutting It All Together: Small Core M
Next to power constraints, the final element of Intel’s fanless challenge is the size of the SoC itself. Sub-10mm thickness doesn’t just put constraints on the heat capacity of the device but it also constrains just how large an SoC and its supporting circuitry can be. As a result Intel has focused on making Broadwell-Y the smallest Core processor yet, making the entire SoC under 500mm2 in size.
As was the case with power, reducing the size of Broadwell-Y is a multi-faceted effort. The 14nm process plays a big part here, allowing for one of the smallest Core CPU dice yet. At 82mm2 the Broadwell-Y CPU die is some 37% smaller than the Haswell-Y CPU die, none the less packing a dual-core CPU and a full GPU slice.
With such a small die Intel was in turn able to reduce the size of the entire SoC package through the combination of the reduced die area and further optimizations to the packaging itself. Haswell-Y’s already small ball pitch of .65mm was further reduced to just .5mm, producing a package with Intel’s smallest solder ball pads yet. Intel considers the reduction in the ball pitch to be the key change that allowed Broadwell-Y to be so small, as they were already pad-limited on Haswell-Y despite having ample excess packaging even after taking the CPU die’s larger size into account. As a result Broadwell-Y takes up almost 50% less surface area (XY) than Haswell-Y.
Intel has also made a number of changes for Broadwell-Y to reduce the Z-height of the Y SoCs, as even 1.5mm for the SoC starts to become a significant design constraint in a sub-10mm device. Again owing to the 14nm process, the Z-height of the Broadwell-Y die itself is down to 170um. Meanwhile the Z-height of the substrate has been cut in half from 400um to 200um, which accounts for nearly half of the total reduction in SoC Z-height.
The final element in reducing the SoC Z-height, and what’s likely the most unorthodox change for Broadwell-Y’s packaging, is Intel’s 3DL inductors. The 3DLs aren’t just to improve energy efficiency as we discussed before, but they are part of Intel’s efforts to reduce the SoC size. For Broadwell-Y the 3DLs are on their own PCB on the back of the SoC, extending well below the back of the package. To accommodate this, logic boards housing Broadwell-Y will have a hole in them where the 3DL PCB would be in order to allow the complete SoC to fit. Because there are no BGA connections here this change isn’t quite as radical as it first appears, but it’s a very good example of just what lengths Intel was willing to go to reduce the package Z-height.
All told then, the combination of these space optimizations has reduced Broadwell-Y’s Z-height by nearly 30%, from 1.5mm on Haswell-Y to 1.04mm on Broadwell-Y (3DL PCB not included). By bringing Broadwell-Y’s thickness under 1.1mm, the SoC is now no taller than the other common components on a logic board (e.g. RAM), meaning the SoC will no longer stick out above the other components, which is useful both for saving space and for allowing simpler (flatter) heatsinks.
Finally, the smaller size of the Broadwell-Y package will also have a knock-on effect on the size of the logic board, further feeding into Intel’s goals to get Broadwell-Y into smaller devices. Intel tells us that the size of a complete platform (logic) board for Broadwell-Y has been reduced by roughly 25% as compared to Haswell-Y, allowing Broadwell-Y to better fit into not just thinner devices but overall smaller devices too.
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psyq321 - Tuesday, August 12, 2014 - link
Actually, apart from power-users I fail to see any tangible improvements in performance of modern CPUs that matter to desktop/notebook usage, Intel or otherwise.In the mobile space, it is improvements in GPU which mattered, but even that will eventually flatten once some peak is reached since graphics improvements on 4" / 5" screen can only matter to wide audiences up to some point.
However, there are surely enough customers that do look forward to more power - this is workstation and server market. Skylake and its AVX512 will matter to scientists and its enormous core count in EP (Xeon) version will matter to companies (virtualization, etc.).
Standard desktop, not so much. But, then again, ever since Core 2 Quad 6600 this was the case. If anything, large-scale adoption of SSDs is probably the single most important jump in desktop performance since the days of Conroe.
Khenglish - Monday, August 11, 2014 - link
I find the reduction in die thickness to be a big deal. Maybe this will prevent temperatures from getting out of control when the cpu core area gets cut in half for 14nm. High power 22nm cpus already easily hit 30c temperature difference between the cpu and heatsink.AnnonymousCoward - Tuesday, August 12, 2014 - link
Probably not. I'd guess thermal dissipation is the same.dgingeri - Monday, August 11, 2014 - link
PC sales are down mostly because people can keep their systems longer due to the lack of innovation coming from Intel on desktop chips and the lack of utilizing the current CPU technology by software developers. They could be so much more, if only developers would actually make use of the desktop CPU capabilities for things such as a voice command OS that doesn't need to be trained. Intel would then have a reason to produce more powerful chips that would trigger more PC sales.As it is, the current processor generation is less than 10% faster clock for clock compared to three generations ago. A great many thing aren't any faster at all. Know what? It doesn't even matter because nothing uses that much power these days.
Tablets and smartphones can't take the place of full PCs for most people. Their screens are just too small. Perhaps the younger generations prefer the small form factors right now, but give them a little time, and their eyes won't let them use such things. I can see the move to laptops, especially with 14-15" screens, but trying to show the same content on a 10" screen is just near unusable, and a 5" smartphone screen is just downright impossible. However, desktop PCs still have their place, and that's never going to change.
This push by "investors" for the tablet and smartphone market is just asinine. Broadwell isn't going to help sales all that much. Perhaps, they might sell some more Intel based tablets, but it won't be all that much of an improvement. Tablets have a niche, but it really isn't that much of one.
HanzNFranzen - Monday, August 11, 2014 - link
Tablets are a niche and not much of one? lol yea ok... well while you were asleep in a cave, over 195 million tablets were sold in 2013 between Android/Apple/Microsoft which is just shy of 80 million more than the previous year. World wide PC sales totaled 316M units, so we are talking nearly 2 tablets for every 3 PC's sold. Eh...small niche...dgingeri - Monday, August 11, 2014 - link
yeah, lots of people have them, but how much do they really use them? I have two, one Android and one Windows RT, and I only use them for reading books or for reading the web news while away from home. The Windows unit showed promise, since I could use it to run Office and terminal programs, but I ended up not using it at work anymore because it couldn't use a USB to serial adapter for talking to switches and raid arrays. It ended up being only half useful. They're nice to have for certain things, but they aren't as versatile as a PC. My parents own two, and two PCs, and they use the PCs far more. My older sister has one, and she barely uses it. Her 7 year old uses it to play games most of the time. My nephew has one, and he's only ever used it to read Facebook. It's a telling tale that everyone I've known who has one only has limited used for it.mapesdhs - Monday, August 11, 2014 - link
Point taken, but if people are *buying* them, irrespective of whether they use them,then it doesn't really matter.
Besides, this whole field of mobile computing, smart phones, tablets, now phablets,
etc., it's too soon to be sure where we're heading long-term.
Many people say the copout porting of console games to PCs with little enhancement
is one thing that's harmed PC gaming sales. This may well be true. Now that the newer
consoles use PC tech more directly, perhaps this will be less of an issue, but it's always
down to the developer whether they choose to make a PC release capable of exploiting
what a PC can do re high res, better detail, etc. Wouldn't surprise me if this issue causes
internal pressures, eg. make the PC version too much better and it might harm console
version sales - with devs no doubt eager to maximise returns, that's something they'd
likely want to avoid.
Ian.
az_ - Monday, August 11, 2014 - link
Ryan, could you add a size comparison to an ARM SOC that would be used in a tablet? I wonder how close are Intel in size. Thanks.name99 - Tuesday, August 12, 2014 - link
BDW-Y is 82 mm^2. The PCH looks like it's about a third of that, so total is maybe 115 mm^2 or so.In comparison, Apple A7 is about 100 mm^2.
A7 includes some stuff BDW-Y doesn't, and vice versa, so let's call it a wash in terms of non-CPU functionality.
BDW-Y obviously can perform a LOT better (if it's given enough power, probably performs about the same at the same power budget). On the other hand it probably costs about 10x what an A7 costs.
Krysto - Tuesday, August 12, 2014 - link
Sure, also let's conveniently forget that Broadwell Y benefits not only of 3D transistors, but a 2 generation node shrink, too, compared to A7. Now put A7 on 14nm and 3d transistors...and let's see which does better.This is the issue nobody seems to understand, not even Anand, or just conveniently ignored it when he declared that the "x86 myth is busted". At the time we were talking about a 22nm Trigate Atom vs 28nm planar ARM chip, with Atom barely competing on performance (while costing 2x more, and having half the GPU performance). Yet Anand said the x86 bloat myth is busted...How exactly?! Put them on the same process technology...and then we'll see if x86 myth is indeed busted, or it's still bloated as a pig.