PCI Express 4.0 , no more power cables needed , plug and play GPUs for mining and portable gaming

PCI Express 4.0 Brings 16 GT/s And At Least 300 Watts At The Slot

The next iteration of PCI Express will double  the bandwidth per lane, but that shouldn't surprise anyone. During Intel  Developers Forum, we sat down with Richard Solomon, Vice President of  PCI-SIG, and found the hidden gem in the next specification; it provides  at least a 4x increase in power delivery at the slot, which might  eliminate the need for auxiliary power cables with some GPUs.  

The PCI-SIG consists of more than 730 paying members that provide  input and a board of directors that help steer the process. The  standards body is just "days away" from releasing version 0.7 of the  PCIe Express 4.0 specification to members, according to Solomon. The  final specification should come by the end of 2016, but the group will  have an additional 0.9 step in between before completion at 1.0. Some  companies, such as Mellanox, are shipping leading-edge PCIe products  with the 0.7 spec, but will update when version 1.0 arrives. The group  is already working on PCIe 5.0  

As we sat through our presentation with Salomon, I kept thinking back  to the AMD Naples server motherboard the company displayed the previous  night. AMD didn't want to divulge too many details about the next  generation server platform, but a picture is worth a thousand words. If  you look closely, there is a single 20-pin power connector like any  other modern motherboard. There are also four 8-pin and two 6-pin power  connectors. AMD marked the PCIe power connectors as follows: 

P0 ABCD PWR
P1 ABCD PWR
P0 EFGH PWR
P1 EFGH PWR 

These connectors are in addition to the processor 4+4 pin connector  marked P0 and P1 CORE PWR. Even with a 64-core platform, that much power  for the board and processors would severely limit AMD's chances of  getting into data centers. We feel that AMD added the extra power for  something else, like the PCIe edge connectors. When we asked the PCI-SIG, we received the news that for the first  time, PCIe will get a massive power increase at the connector. Solomon  couldn't recall the exact ceiling because member companies have proposed  several options. Solomon stated that the minimum would be 300W, but the  ceiling “may be 400 or 500W." Even with the minimum 300 watts, there is more than enough power  provided by the edge connector to run a GeForce GTX 1080 (reference  design 180 watts) and Titan X (250 watts) without an external power  source. PCI Express 3.0 provides a maximum of 75 watts thus far, though  many slots support the default 25W. The rating for a x16 lane card comes  from 3 amps at 3.3 volts and 5.5 amps at 12 volts, which is a rating  that dates back to the introduction of PCI Express 1.0a in 2003.  

The next iteration of the PCI Express standard will officially pass  the 1-gigabyte bandwidth mark and knock on the door of 2 gigabytes per  second, per lane, per direction. The performance shifts from 3.0 to 4.0  while x16 devices like video cards get a massive headroom increase that  will aid in providing the bandwidth needed for next generation virtual  and augmented reality. PCI Express is a full-duplex protocol that can  send and transfer data at the same time. The speeds listed above are for  single direction performance. PCIe 4.0 uses the same encoding scheme as  PCIe 3.0.  

PCI Express 4.0 Usage

                        

PCI Express has moved well beyond video cards. Currently, nearly  every IO device routes through PCIe to send signals back to the CPU. We  expect to see rapid adoption of the new standard for storage and  networking products.  NVMe SSDs using PCIe 3.0 x4 recently reached the usable limit of the interface, such as the Samsung SM961  that reads data at 3,100 MB/s. Enterprise NVMe SSDs using the add-in  card form factor and bifurcation will ship later this year with PCIe 3.0  x16. The increase in throughput will allow manufacturers to reduce  costs by delivering the same performance with half the number of PCIe  lanes. Analyst firm Forward Insights predicts enterprise PCIe storage  devices will surpass the number of SATA products shipped between 2017  and 2018.   At Computex 2016, Marvell told us to expect consumer networking  products with 10-gigabit speeds in January (CES time frame). 10GbE will  finally fall out of the enterprise sector and into the laps of us at  home and provide roughly 1GB/s of data transfer speeds over commodity  CAT 6 cabling. A single 10GbE connection will only require a single PCIe  lane with the 4.0 specification.  Mobile, Internet of Things (IoT), and other battery-operated devices  will benefit from low-power states and a new focus on burst performance.  PCIe 4.0 adapts new L1 sub-states with half- and quarter-swing bursts,  which use just 400 and 200-millivolt steps.  

Connecting External Devices Through A Standardized PCIe Cable

 

        

During the last year, we've seen a number of companies build external  graphics housings that route back to a small form factor PC via  external cabling. The big fear is that a product from Company A will not  work with a product from Company B. The PCI-SIG looks to end  interoperability issues with the OCuLink standard.   Storage systems will also adopt the PCIe-over-cable OCuLink  connection. The cable is more graceful than SATA Express and the  reworked SAS cables that we currently use for U.2 devices.  

Sources :

http://www.pcmag.com/news/347163/pcie-4-0-will-arrive-in-2017

https://www.plda.com/market-ready-conquer-pcie-40-challenges

http://kgames.co.za/2016/08/19/pcie-4-0-coming-next-year-intel-kaby-lake-cpu-details-leak/

http://www.pcgamesn.com/pcie-4-release-date

http://www.tomshardware.com/news/pcie-4.0-power-speed-express,32525.html

http://www.techspot.com/news/66048-pcie-40-make-auxiliary-power-cables-gpus-obsolete.html

https://en.wikipedia.org/wiki/PCI_Express