Intel Broadwell micro-architecture

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Broadwell (micro architecture)
Manufacturer Intel
Manufacturing process 14 nm
base Socket 1150
Core i3, 5th generation
Core i5, 5th generation
Core i7, 5th generation
Cores / threads 2/4
L1 cache 32 + 32 KB per core
L2 cache 256 KB per core
L3 cache 2/3/4/6/8 MB
predecessor Ivy Bridge (tick)
Haswell (tock)
successor Skylake (tock)
Kaby Lake (optimization)

Broadwell is the code name of a processor microarchitecture from the chip manufacturer Intel , which was published in the fourth quarter of 2014 as the successor to the Intel Haswell microarchitecture . Unlike Haswell, which is based on the 22 nm process, Broadwell is based on a 14 nm process.


Broadwell works with the 1150 socket (LGA 1150), in particular with the H97 and Z97 chipsets released in May 2014 . A common weakness of Haswell processors is that they overheat a lot under full load. The Broadwell processors based on the 14 nm process, on the other hand, should be designed in such a way that some models would get by without a fan.

CPU architecture improvements

Compared to Haswell , various improvements have been made on the CPU side, which lead to a 5% improvement in the IPC . The CPU cores should be better fed with larger instruction schedulers and buffers , and the out-of-order scheduler window has been expanded from 60 to 64 entries to enable more commands to be reordered. The level 2 cache translation buffer was expanded from 1000 to 1500 entries in order to reduce address translation misses.

A second miss handler was added for TLB pages, so that Broadwell can use both handlers in parallel to move through memory pages. There is also a 1 GB page mode, which is primarily important for servers (in addition to the 4 KB and 2 MB pages at Haswell). The branch prediction has also been optimized to reduce mispredictions and unnecessary memory operations.

Thanks to improvements in the corresponding hardware block, the latency of a floating point multiplication could be reduced from five to three clock cycles, the division could be accelerated by using a larger radix 1024 (10 bit) divider.

GPU architecture improvements

Like Haswell GPUs, Broadwell GPUs are organized into various sub-areas, which Intel calls slices. In contrast to Haswell, the Intel HD Graphics 5300 (the official name of the 8th generation) consists of one slice with three sub-slices instead of two. Instead of ten, each sub-slice now has eight execution units (EUs) consisting of 2 × 4 vector SIMDs with their own local thread dispatcher, instruction cache and their own texture sampler unit, including dedicated L1 and L2 caches. The load / save operations run via the data port, which can read and write 64 bytes per clock cycle. The number of EUs has thus increased by 20% from 20 to 24. The ratio of L1 cache and sampler was increased relative to the EUs. The sampler throughput increased by 25% per EU, in total by 50% with the same clock frequency.

To save energy, duty cycling was introduced, in which the GPU only runs for up to 12.5% ​​of the total time in active mode and is completely switched off for the rest of the time. Duty cycling is invisible to the applications and users because the display controller is decoupled from the GPU clock supply. It is controlled by the GPU hardware and Intel's graphics drivers.

Broadwell's GPU also supports OpenCL 2.0. including shared virtual memory. Since Intel does not have a programming model like AMD's HSA (where the CPU and GPU cores are supposed to process universal tasks together), it is now easier to combine CPU and GPU and better utilize them by sharing complex data structures instead of between CPU and GPU - Having to copy memory back and forth.

SpeedStep problems

According to a Heise online article, many users report Machine Check Exceptions (MCE) on Broadwell processors, especially under Linux . Ubuntu 14 seemed to be affected most often, Fedora 22 less often. Systematic Windows crashes (blue screens) were also reported under Windows, for example when installing Office 2016 or with some Steam games. The problems mostly disappeared when you switched off SpeedStep .

Broadwell generation chipset

For the Broadwell generation, the Intel 9 series chipsets, which the Haswell generation also supported, can still be used. Of these, the Z97 and H97 are required for all Core-i3 / i5 / i7-5xxx models, the new X99 chipset (code name Wellsburg) is required for the Broadwell-E (i7-6xxx) models.


Web links

Individual evidence

  1. Mark Mantel: CPU Roadmap 2016–2018. PC Games Hardware, August 8, 2016, accessed August 22, 2016 .
  2. ^ Nico Ernst: Ultrabooks with Broadwell in October 2014., May 21, 2014, accessed on August 24, 2014 .
  3. Florian Müssig: Intel Roadmap: Core M comes in autumn, Broadwell Ultrabooks not until 2015. Heise, July 4, 2014, accessed on August 25, 2014 .
  4. Sam Reynolds: Intel's 9-series chipsets will support Broadwell. (No longer available online.) VR-Zone, August 26, 2013, archived from the original on November 20, 2013 ; accessed on August 25, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  5. ^ Matthew Lambert: The Intel 9-Series Chipsets Examined. Bit-Tech, May 11, 2014, accessed August 25, 2014 .
  6. Hassan Mujtaba: Intel Broadwell Compatible With 9-Series Based Z97 and H97 Chipsets - Brings New SATA Express 10 GB / s. WCCF Tech, accessed August 25, 2014 .
  7. Björn Greif: Intel brings more than 40 new Haswell processors. ZDNet, April 15, 2014, accessed on August 23, 2014 .
  8. Haswell is getting too warm. June 11, 2013, accessed August 22, 2014 .
  9. Stefan Beiersmann: Core M: Intel announces the first Broadwell chip for fanless PCs. ZDNet, August 12, 2014, accessed on August 25, 2014 .
  10. Andreas Stiller: Intel reveals details about Core-M with Broadwell core. Heise, August 11, 2014, accessed on August 24, 2014 .
  11. a b Frank Riemenschneider: Intel's Broadwell micro-architecture and Core-M-SoC revealed. elektroniknet, September 12, 2014, accessed on September 15, 2014 .
  12. Andreas Stiller: Furthermore SpeedStep problems with Broadwell processors. Heise, October 9, 2015, accessed October 10, 2015 .
  13. Michael Larabel: Working Around The Intel Core i7 5775C Broadwell Stability Issue On Linux. Phoronix, July 5, 2015, accessed October 10, 2015 .
  14. Intel: Intel® Z97 chipset. In: Intel Product Specification. June 1, 2014, accessed September 27, 2017 .
  15. Intel: Intel® H97 chipset. In: Intel Product Specification. June 1, 2014, accessed September 27, 2017 .
  16. Intel: Intel® Z99 chipset. In: Intel Product Specification. September 1, 2014, accessed September 27, 2017 .