JAN 2022 MAXIMUMPC 95
a GPU-spec controller
to a CPU with integrated
graphics. The GDDR
memory used with GPUs
has great throughput
or bandwidth but poor
latency, while the DDR
memory that’s hitched up
to CPUs is the opposite—
low latency but limited
throughput. The solution
would be a best-of-both-
worlds combination of the
bandwidth of VRAM with
the low latency of DRAM.
Actually, it’s more or
less been done. Apple’s
new M1 Max SoC has
both CPU cores and
GPUs that share a single
memory subsystem
offering 40 0GB/s of peak
throughput, courtesy of
LPDDR5 RAM running over
a 512 -bit controller. It’s
hard to compare graphics
performance between Mac
and PC, but the integrated
GPU in the M1 Max is as
fast as an Nvidia RTX 3060
desktop GPU and so far
faster than any existing PC
integrated graphics.
Another example is the
latest games consoles,
which have integrated
GPUs sharing memory
bandwidth with CPU
cores. However, both the
Microsoft Xbox Series
X and the Sony PS 5 use
GDDR6 graphics memory
shared between the CPU
and GPU. That works for a
games console but could be
problematic for a PC with
add-in memory.
In a console, the memory
can be packaged close to
the SoC, helping reduce
latency. All of this means
that high-performance
integrated graphics is
possible on the PC, but will
probably require some loss
of configurability.
Achieving performance
levels good enough
for high-quality gaming
will likely require CPU
and system memory
to be packaged and
sold together as a unit,
preventing users from
upgrading one but not
the other.
Hard drives and the
theoryof speed
I am trying to transfer
pictures from one HDD to
the other, but I am having
problems with the transfer.
They are supposed to be
able to transfer at the rate
of 6GB/s, but it is taking
hours. I wonder why these
drives never seem to run
at that speed? My system
includes an MSI X47 0 AMD
Gaming M7 AC mobo, AMD
Ryzen 7 27 00x CPU, Corsair
Dominator 32 GB 30 00MHz
RAM, 2x Seagate 50 0GB
SSHD ST500LM000-1EJ162,
all running Windows 10
64-bit. – EdwardMAXIMUM PC EDITOR,
JEREMY LAIRD RESPONDS:
Part of the problem here
is theoretical versus
actual real-world speed.
Your drives are likely to
be based on the SATA III
protocol with a theoretical
maximum throughput of
6Gb/s—that’s Gb/s, not
GB/s, which are an order
of magnitude apart.
Anyway, that 6 Gb/s
refers to the theoretical
maximum speed of the
SATA III protocol rather
than the hard disk itself.
It determines the maximum
bandwidth available to
the drive. The actual
bandwidth available is a
little lower due to protocol
overheads. In theory,
SATA III provides around
600MB/s of bandwidth,
but the fastest transfer
speed is around 550 MB/s
to 560 MB/s. Of course,
those kinds of figures are
achieved by solid-state
drives. Typical HDD speeds
are 200 MB/s or lower for
both reads and writes.
Even the fastest HDD
yet, the Seagate Mach.2,
designed for data centers,
tops out at 52 4MB/s, but
only for data stored at the
edge of the platters.
Of course, even around
150 MB/s should be enough
for transferring a lot of
images fairly quickly.
Slightly confusing the,
er, picture here is thatyour drives are 500 GB
Seagate SSHDs or hybrid
drives with 8GB of MLC
NAND memory designed
to improve performance to
solid-state levels in certain
scenarios. That NAND
memory will help with
short, sharp random disk
access, the kind of traffic
that dominates day-to-day
computing. However, for
sustained transfers, the
underlying performance of
the hard drive is exposed.
That said, Seagate
claims your drives are
good for average data
throughput of 100 MB/s,
which ought to be enough
for transferring files at
a reasonable pace. The
fact that it’s taking hours
implies either a hardware
issue or some kind of
configuration problem.
If your SSHD drives are
old, the NAND memory
may be wearing out.
Another candidate could be
your SATA configuration.
It’s worth checking that
the drives are attached
to the primary chipset
controller rather than an
add-in controller if your
motherboard has multiple
SATA controllers. Refer to
your motherboard manual
for the optimal SATA
configuration for multiple
drives. Drive contention
can impact performance
dramatically.
Also, make sure that
your motherboard’s BIOS
is running in the correct
mode for your drives.
Typically, the default
configuration will be
correct, so resetting to
global BIOS defaults is the
easiest option. However, be
sure to get a snapshot of
your BIOS settings before
making any changes at
all. Depending on whether
you built and set up your
system yourself, there
may be settings you aren’t
aware of that are required
for a successful boot.
If in any doubt, the safest
option is not to touch the
BIOS settings and get some
expert help instead.Baffling blueprints...
On the basis of Maximum
PC content generally being
several notches above my
pay grade and there being
no fool like an old fool,
please consider this when
answering my question. In
"The Builds" at the back of
the magazine, why does the
Intel Ingredients list always
show GPU: AMD Radeon
for Mid Range and Turbo
builds? Yet the AMD list
shows Nvidia? I do learn
an immense amount from
the magazine, but must be
missing something.- J. Watson
MAXIMUM PC EDITOR,
JEREMY LAIRD RESPONDS:
Not at all. There’s a lot to
parse in the Blueprints
section. The most
important aspect to grasp
is that the ‘Intel’ and
‘AMD’ builds refer to the
vendor responsible for the
platform, rather than GPU.
In practice, that means an
Intel or AMD motherboard
chipset and CPU. Into
that, any compatible
and relevant GPU can be
slotted. Next year, that
will hopefully also include
Intel’s new graphics cards,
for which we have high,
though cautious, hopes.
These builds are
constantly under review,
which is a tricky task of
late given the difficulty
and expense of sourcing
graphics cards. But at
any given moment and
price point there tends
to be a GPU that stands
out as delivering the best
combination of value and
performance. At the high-
end, for instance, Nvidia's
RTX 3090 boards are
arguably overpriced, so the
AMD Radeon RX 6900 XT
gets the nod.
There’s no intention to
have exclusively AMD or
Nvidia GPUs in any given
slot, but graphics card
refreshes don’t come
along often, so changes in
that area will necessarily
be periodic rather than
routine!