If you’re an enthusiast like me, you must be aware of the
ongoing controversy over the boost-clock speeds of AMD’s recently launched
Ryzen 3000 series processors. What started with some early adopters finding it
hard to hit the rated boost frequencies on their respective Ryzen CPUs has now
found its way into more serious contention, supported by claims from both
reliable and unreliable sources. Things have specially heated-up after well-known overclocker “der8auer” conducted a survey which puts a big
question mark on the ability (or the lack there-off) of most 3rd gen
Ryzen CPUs to operate at their advertised max boost-clock! While this
controversy doesn’t necessarily jeopardize Ryzen’s status as the current champ
of desktop processors on the whole, it sure creates a cloud of confusion or two
in the mind of average consumer and enthusiast alike. Here we’ll try to dispel
any such confusion by going deep into the matter and seek the truth.
First of all, we need to understand that this isn’t a single
isolated issue; rather, a bunch of vectors are likely at work here, making
things look more complicated than they actually are. Among those will be –
Ryzen’s design principles, the new boost-clock algorithms, cooling and
thermals, BIOS and Windows optimization and of course silicon lottery and
binning. Any of these can play an important role when it comes to processor
clock-speed, and, in the case of Ryzen 3000 chips, probably all of these are
involved at some level or other.
Core of the matter - Zen 2, Precision Boost 2.0 and others: Back in
July, when Ryzen 3000 was launched along with a flurry of gushing reviews, one
thing was clear from the get go – these’re not the speed demons that many
thought them to be -clock-speed wise. Coming from Ryzen 2000, there is the
incremental bump of couple of hundred MHz across the range but more importantly
the new Zen 2 cores (codename “Matisse”) at the heart of every Ryzen 3000
series processors don’t rely solely on blazing fast frequencies to deliver
competitive performance, unlike Bulldozer/Piledriver. Instead, this time around
AMD has delivered a “proper” core with a strong emphasis on IPC (Instruction
per Clock-cycle) and efficiency – one that clock-for-clock can match and even
surpass Intel’s best! This is a conscious design trade-off and as such AMD has
made sure to extract every last MHz from TSMC’s 7nm process. Ryzen 3000 chips,
specially the highend ones like Ryzen 9 3900X, Ryzen 7 3800X and Ryzen 5 3600X
are clocked to their limits and have very little overclocking headroom left.
This is where Precision Boost 2.0, as AMD likes to call it,
comes into play. Automatic core-clocks boosting algorithms are common place
these days, both in CPUs and GPUs. The latest iteration of Precision Boost (PB)
however is particularly dynamic and opportunistic. Introduced with 2nd
gen ThreadRipper/Ryzen, PB can heighten the core-clocks far beyond the rated
base-clock under lightly threaded (think 1 or 2 cores) workloads, provided
there is thermal headroom left to do so. PB is a part of AMD’s SenseMI technology
which constantly monitors hundreads of sensors employed throughout the
processor silicon. It can also kick-in under heavily threaded but the boost
will be significantly lower compared to when fewer number of cores are active.
This is analogous to Intel’s own Turbo Boost which used to be far superior
compared to AMD’s implementations, but with PB AMD has now has its answer.
Let’s have look at the specs of 3rd-gen Ryzen CPUs to have a clear
idea of how much Precision Boost facilitates clock rates.
CPU
|
Core/Thread
|
Base Clock (GHz)
|
Boost Clock (GHz)
|
L3 Cache
(MB)
|
TDP
(Watt)
|
Ryzen 9 3900X
|
12C/24T
|
3.8
|
4.6
|
64
|
105
|
Ryzen 7 3800X
|
8C/16T
|
3.9
|
4.5
|
32
|
105
|
Ryzen 7 3700X
|
8C/16T
|
3.6
|
4.4
|
32
|
65
|
Ryzen 5 3600X
|
6C/12T
|
3.8
|
4.4
|
32
|
95
|
Ryzen 5 3600
|
6C/12T
|
3.6
|
4.2
|
32
|
65
|
As you can see, every Ryzen 3000 CPU released till date can
reach significantly higher clock-speed. The Ryzen 9 3900X and Ryzen 7
3700X in particular can clock 800MHz higher than their base rating while others
get a boost of 600Mhz. Needless to say that Precision Boost makes a huge
difference in overall performance and efficiency, especially when it comes to
your PC being more snappy and responsive. When you think that many general
purpose apps and games still rely on single-thread performance, this is a big
deal.
An interesting point here is the omission of XFR (eXtended
Frequency Range), -an auto-overclocking algorithm that made its debut with the
original Ryzen (1st gen), carried along with the Zen+ refresh (2nd
gen) and, at-least in theory could increase processor clock-speed even beyond
the rated boost-clock! Instead, with Ryzen 3000 series AMD has introduced a
couple of new mechanisms - Precision Boost Overdrive (PBO) and Auto Over-Clock
(AOC). Off by default, these can be found both inside your motherboard BIOS and
AMD’s own tuning software “Ryzen Master”. Despite the naming alikeness, these
are quite different from Precision Boost, both in purpose and functionality and
have more common with the MultiCore Enhancement (MCE) mechanism found in Intel
motherboards. Thanks to AMD’s confusing naming and implementation, it’s very
easy to mix things up!
Precision Boost 2.0 with new features |
While this YouTube video should give more insights into the
workings of PBO and AOC, we believe AMD should provide some clear and
easy-to-understand guideline for optimizing frequency of Ryzen 3000 processors,
preferably with hands-on example. But for now, let’s be clear - When people are
claiming inability to hit advertised clock-speed, they are (or should be)
talking about Precision Boost (PB) and not the others.
Max Boost Frequency – thermal limitation and cooling: Speaking of boost
frequency, One little thing that’s very easy to miss is how Intel and AMD
advertise the max boost-clock of their respective processors. On retail
packages and product lists, it says “up to X.XX GHz” meaning that the chip in
question is capable of reaching that speed. That however doesn’t warrant you’ll
be hitting those frequencies in a plug n play manner! Boosting algorithms such
PB are inherently limited by thermal constrains which means even if the
conditions are right, you can’t expect to see your core-clock rise to its
zenith if you don’t have sufficient cooling. Proper cooling doesn’t only help Precision
Boost to kick-in it can also provide sustenance at its highest achievable
frequency. Electrical (energy) limitation is a factor too but that’s more of
multi-core thing and should not affect lightly threaded scenarios. You still
want to invest in a motherboard with capable VRM (voltage
regulator module) array to make sure that the plenty of current
available to the processor to sustain a boost state for longer period of time.
The bundled Wraith Prism is a capable little cooler |
So what then qualifies as proper cooling, you may ask. From
what we’ve seen AMD’s own Wraith coolers are pretty impressive considering these
come bundled with Ryzen CPUs. When it comes to attaining the maximum boost, a
hefty 360mm all-in-one liquid cooler will definitely fare better compared to
the “free” Wraith, but not by a huge a margin. Here
is a test to prove that not only Wraith coolers are awesome value additions
but these are enough for Precision Boost to work its magic. But there are other
factors like ambient temperature, case airflow and mounting of the cooler
itself which can and will impact the final outcome.
With highend models, as the number of cores and clock-speed
start to scale-up, the role of your cooling set-up becomes even more crucial. This
applies equally to Intel and AMD. It takes nothing short of a dual fan 280mm
AIO liquid cooler for Intel’s i9 9900K to sustain its boost frequencies and
even then you’ll only see it occasionally hit the advertised 5GHz!
The silicon lottery - not two CPUs are made the same: Turns out
neither are two cores, at least in case of 3rd gen Ryzen! When Tom’s
Hardware enquired into the matter, they found that not every core inside their
retail Ryzen 5 3600X are capable of hitting the chip’s rated 4.4 GHz boost
clock! It goes to show that a Ryzen 3000 Core Complex (CCX) is composed of both
slower and faster cores. AMD also has confirmed it. Although the speed gap
between the cores is down to a trivial ~50-75 MHz, it is there. Thankfully
however, the latest versions of Windows 10 comes with a scheduler which in
coaction with AMD’s Ryzen Master software can mitigate this issue by
identifying and assigning threads to the fastest cores within a Core Complex
(CCX). Since the highest extension of Precision Boost is only called upon when
only one or two cores are active, the rest of the cores can clock down and sit
back to provide additional thermal headroom.
Interesting but hardly surprising! During lunch reviews not
many reviewers could get their samples, which are supposed to be cherry-picked,
past 4.3GHz all core overclock -even with some very uncomfortable amount of
voltages. That was the telltale sign of the fact that with Matisse AMD has well
and truly hit the limits of 7nm process node. It is only with some clever
binning at the silicon level that AMD could deliver those max-boost numbers.
And we’re fine with that as long as the CPUs hit those frequencies.
This is also the reason why we’ll advise against manually
overclocking Ryzen 3000 CPUs. Trying so will only net you few hundred MHz on
all core while you’ll lose out on the ability of those faster cores to boost
far beyond what the CPU is capable as a whole. Not a good trade-off!
The state of the early BIOS/AGESA and AMD’s fix: When it comes to performance
optimization of newly launched platform such as Ryzen 3000, the most important aspect
is perhaps the state of its own BIOS. Motherboard makers spend some of their
busiest times during any new processor lunch, integrating copious amounts data
in form of patches, updates and bug-fixes into their mainboard’s BIOS or AGESA (AMD
Generic Encapsulated Software Architecture) as it is called within AMD
platforms. An early BIOS is a work in progress with lots of fine-tuning going
on with each update but it can be a great source of confusion too, specially
among the early adopters who are yet to familiarise themselves to its
intricacies. Have a look at the image billow to understand just how much of an
impact a firmware update or revision can bring about.
Boost-clock scaling with different firmware, image credit - AnandTech |
As you can see, the newer version significantly changes the
boost pattern and causes the same processor to reach higher frequencies within
the same workload. Likewise, an update can potentially impact the performance
negatively too. Just after the launch, there were reports of some users
complaining about their CPU’s high idle temperature. Believing it could be due
to the “overzealous” boost algorithm that was responding to calls from
background apps inside of Windows that don’t actually need the highest
power-stage or the max-boost speed, AMD made a few changes to the firmware
which resulted in a more relaxed boosting behaviour. But some may perceive this
as a regression of shorts. Previously there have similar controversies over Ryzen
specific Windows power plans as well.
AMD too seems to believe that these discrepancies are stemming
from a BIOS issue and has promised to resolve it with an upcoming update. In a
blogpost, the company has stated that the new firmware will fix any regression
in the boost behaviour and will come with further optimization for stable and
efficient operation of Ryzen 3000 series processors. While it may take a few
weeks for the motherboard manufacturers to implement the fix into fully-fledged
BIOS, a few beta versions can be found online and have already been put to the
test. The result shows that AMD’s fix works as intended. But that doesn’t mean
that we recommend flashing with beta BIOS! If you happened to be an owner of 3rd
gen Ryzen processor and had issues attaining the rated max boost-clock, you
should wait until there is a newer and fully working version of BIOS firmware
in your motherboard vendor’s website.
What it means to you: With everything said and done, this whole Ryzen
3000 clock-speed saga could very well be one of those “blown out of proportion”
things! PC hardware industry has a storied history of getting too worked up with
slightest of anomalies; remember the controversies surrounding Nvidia GTX 970’s
V-RAM or Radeon RX 480’s PCIe power draw? Ever since the introduction, the new Ryzen
CPUs have been the most sought-after by enthusiasts and as such have drawn lots
of attention from press too. But at this point it seems like we’re all reading a
bit too much into the matter! That’s not to say all the reports and claims of Ryzen
cores not boosting to their full potential are unsubstantial. There is certainly
an element of authenticity within all this otherwise it wouldn’t have garnered
a response (and a fix!) from AMD. But there are much more confusion and
misinterpretation than there are checked facts and in this article we tried to
bring some clarity on the whole issue.
Whether you already have bought a Ryzen 3000 series desktop
processor or planning to buy one, nothing has changed. Of all the metrics
relevant to a modern CPU, performance is the most important one and the latest Ryzens
have no shortage of that. Just make sure that you have a motherboard with good
VRM arrangement, a proper and well-mounted cooling, latest chipset drivers,
latest windows updates and latest BIOS. Going by the worst possible scenario,
even if your chip boosts a little shy of what it’s rated for, the impact will
be negligible on most use-cases. We liked the Ryzen processors for their remarkable
performance, energy efficiency and value for money and while we’ll definitely
keep an eye on further developments, at the moment, we don’t see any reason to
change our opinion.
No comments:
Post a Comment