Making Computing Faster: Beyond the Processor
When we talk about making computing faster, we
typically think about new CPUs and maybe new graphics processors. These are
very important, but processor speed is far from the only determinant of how
fast your PC feels. The speed in which the processor gets information from
memory, and writes it back, is crucial. And for many tasks, the speed in which
the processor connects to other devices within the device; and the speed in
which it connects to the outside world is a key factor as well. In most cases,
these connections are governed by standards bodies who agree on specifications
that various manufacturers then adopt and implement in their products. Just
about all of these specifications are in the process of significant upgrades.
That’s not to minimize the importance of
processors. Perhaps the most important trend happening is improved
competition in the CPU market. We
have recently seen AMD’s Mobile Ryzen 4000 and Intel’s
Comet Lake-H begin to roll out, while Intel’s bigger changes are slated for
later in the year. But there are big changes coming in other areas as well.
DDR 5 Memory
One of the most important determinants of
performance is memory speed. For DRAM memory, the current standard is DDR4,
which was first published by JEDEC in 2012 and has been updated a few times
since then. The current top speed officially goes up to 3200 MHz, but some
memory makers have been making faster boards, up to 5GHz. However,
this requires particular chips and motherboards, and often comes with decreased
performance in other parts of the system.
JEDEC is currently working on DDR5, which is
aimed at providing double the bandwidth and density compared with DDR4, along
with improved channel efficiency. This should be particularly important for
server applications. It’s likely that the standard will be finalized this year,
but we aren’t likely to see it supported in servers until late 2021 or 2022,
likely in AMD’s Genoa EPYC and Intel’s Sapphire Rapids Xeon Scalable
processors.
PCIe 5 Interconnects
Within your computer, the I/O connection to
things like graphics cards, SSDs, and even Ethernet or Wi-Fi is typically done
using the PCI Express (Peripheral Component Interconnect Express or PCIe)
specification. PCI dates back to the early 90’s, and today, the vast majority
of systems use PCIe 3.0, which was adopted in 2010, and is designed for up to 8
Gigatransfers (GT/s), which works out to throughput of a little less than 16 GB
per second (after overhead) in a standard design with 16 lanes.
The standard pretty much stayed at that speed for
years, but recently, the group behind the standard – the PCI-SIG – has moved to
a more regular cadence, looking for upgrades every 2 to 3 years, according to
Al Yanes, PCI-SIG president and board chair.
In the meantime, though PCIe has begun to be used
in more places, such as the interface for NVMe (Non-Volatile Memory Express)
SSDs, which are now commonplace and provide for a faster connection that the
first generation of SSDs, which typically used hard drive technologies, such as
SATA.
The PCI Express 4.0 standard, which allows for up
to 16 GT/s was adopted in 2017, and products began official testing as of
August. The first major CPU to support PCIe 4.0 was AMD with the Ryzen 3000
series and its accompanying motherboard, and there are now a few SSDs and
graphics boards (such as the AMD Radeon 5700) that support it as well. Intel
has yet to ship a CPU and motherboard that supports this standard (although it
has shown some SSDs), but it is expected
this year or next.
Meanwhile, last May, the SIG announced PCIe 5.0,
which delivers 32 GT/s; and a few companies are now showcasing solutions. These
are still not really in the market, but the group expects adoption to grow in
the next 18-24 months, primarily for high performance applications.
Most recently, the SIG announced that it has
released to members an early version of PCIe 6.0, which doubles the bandwidth
again to 64 GT/s, targeting a 2021 official release. At that speed, a 16-lane
implementation could allow an amazing 256 GB/second.
The reality is that a typical PC doesn’t need
this level of speed, but it’s crucial in servers, particularly in hyperscale
and high-performance computing environments.
USB4
For connecting wired peripherals, USB has been
the dominant standard, and the USB Implementer’s Forum has plans to broaden its
appeal to cover more devices, as well as provide new speed.
Perhaps the biggest change is that Intel’s Thunderbolt
spec is essentially now merging with USB 3.2 to create a royalty-free USB4
standard, as announced
last fall.
Brad Sunders, USB-IF Chairman noted that
Thunderbolt 4 and USB 4 would essentially be the same standard, with different
devices able to scale the bandwidth and still be backwards compatible with the
earlier USB 3.2, USB 2, and Thunderbolt 3 standards. On older USB Type-C cables
with two lanes, this should provide up to 20 Gigabits per second (Gbps), but
with newer cables, it should provide up to 40 Gbps operation.
The Forum hopes to distinguish the two with new
branding. The new specification is officially called USB 4, but the packaging
will be different depending on whether it supports 20 Gbps or 40 Gbps; and
whether the port supports charging (with a new logo designed to look somewhat
like a battery).
Saunders noted that USB can be used for both data
and displays, with the ability to run DisplayPort through a USB cable.
Perhaps the biggest push was for USB charging,
include certified fast chargers. This is designed to let smartphone OEMs better
manage the thermals, using what is called the Programmable Power Supply (PPS)
function of the USB Power Delivery 3.0 specification. This is quickly becoming
a standard for laptops and phones (except for the iPhone).
Bluetooth LE Audio
For connecting devices wirelessly, whether to a
PC or a phone, Bluetooth is the standard, and has been around for 20 years. In
recent years, there has been a lot of focus on Bluetooth LE (low-energy),
sometimes called BLE. This standard has been good for many connections, such as
mice, keyboards, and remote controls, but wasn’t really suitable for audio. At
CES, the Bluetooth SIG announced LE Audio, which allows both wireless data
transfer and audio streaming using a single mode Bluetooth LE radio.
This includes a new Low Complexity Communication
Codec (LC3), designed to deliver high-quality audio at lower power consumption.
The codec is supposed to be better than the SBC codec used in most standard
Bluetooth audio while using less power, but not as good as the Advanced Audio
Codec (AAC) or aptX codecs used in high-end headphones. But perhaps the big
advantage is that it will
now work with hearing aids.
Another big new feature is Broadcast Audio, which
lets an audio source device (like a PC smartphone) send the same audio stream,
or a number of audio streams, to an unlimited number of audio sink devices
(like headphones or speakers) within its range. This should allow things like
letting you tune into the audio on the specific game you want to watch at a
sports bar. It could be very cool. And it also enables personal audio sharing,
so you can share audio from your phone to other people.
The Bluetooth SIG plans to release the final
specifications for LE Audio in the first half of the year, with devices that
support the spec expected by year end.
Wi-Fi 6
For connecting wirelessly to the Internet, the
big new standard is Wi-Fi 6, the latest generation of Wi-Fi, as labelled by the
Wi-Fi Alliance and based on the IEEE
802.11ax standard. This launched in the fall, and is designed to offer four
times the capacity of the previous Wi-Fi 5 (802.11 ac) standard, with theoretical
speeds near 10 Gbps vs. 3 Gbps for 802.11ac.
While speed is the headline, generally most
people are limited by the speed of their Internet connection. However, within
an environment, there has been an issue with network congestion. Wi-Fi 6 adds a
new feature called orthogonal frequency division multiple access (OFDMA)
modulation, which allows up to 30 clients to share a channel at the same time. This
is most important when you have a lot of devices all using the network at the
same time.
Other new features include Target Wake Time
(TWT), which lets devices determine when they will wake up to begin sending and
receiving data. This should extend battery life on smartphones and tablets, as
well as on IoT devices such as cameras and video doorbells.
Wi-Fi 6 is supported in the currently shipping
chipsets for both AMD Mobile Ryzen 4000 and Intel 10th Generation Core
CPUs. Initial testing
showed that the new standard is notably faster than the earlier 802.11ac
standard. Of course, you’ll need both a capable router and devices to take advantage
of it.
Earlier this year, the Wi-Fi Alliance announced
new terminology called Wi-Fi 6E for devices that not only support the
traditional 2.4 GHz and 5 GHz bands, but also the 6 GHz band. A number of
regulators around the world have talked about opening up this spectrum. In the
U.S., the FCC has just proposed making a lot of spectrum available to
unlicensed uses (such as Wi-Fi) including 1,200 megahertz of spectrum for
low-power indoor use and 850 megahertz of that spectrum band for standard power
devices. A vote on this is now scheduled for later this month. Wi-Fi 6 devices
are now readily available; Wi-Fi 6E will require new devices, of course, but
the first
chips are beginning to appear
