you can set only a small numbers of cores to
reach the maximum overclock.
Another drawback of manual overclocking
particularly affects AMD CPUs. Unlike Intel,
AMD runs its CPUs fairly close to their limits
at stock speed, and as a result they often
don’t overclock very far. Many even fail to
hit all-core overclocks that are the same
frequency as their stock speed single-core
boost frequencies, which can result in a
drop in single-core performance. Add in the
fact that, like Intel CPUs, AMD’s frequency
boosting technologies are disabled when you
overclock and you end up with a much more
power-hungry CPU for potentially a drop in
single-core performance, although multi-core
performance generally sees a decent boost.
This problem with poorer single or lightly
threaded workloads gets worse the higher
up the stack you go. The relatively lowly
6-core Ryzen 5 3600 has a stock boost
frequency of 4.2GHz but can just about be
pushed to overclock all cores to 4.3GHz.
Meanwhile, the monstrous 16-core Ryzen
9 3950X has a single-core boost frequency
of 4.7GHz, but 4.4GHz is usually the limit for
an all-core manual overclock, meaning you
lose out on 300MHz.
It’s still worth overclocking here if
you need maximum multi-threaded
performance, though, as most AMD CPUs
can reach all-core overclock frequencies far
higher than all cores would reach at stock
speed. A lot depends on your preferences.
WHY INCREASING VOLTAGE
CAN MAKE AN OVERCLOCK
MORE STABLE
Popular misconceptions are that your CPU
might suck more voltage as you increase
its frequency like a car might with fuel if you
tune its engine. However, this isn’t what’s
happening. Transistors in your CPU have a
certain state switching speed and increasing
the CPU frequency reduces the time it takes
for this transition to happen. This wouldn’t
be a problem, except the transistors are
also responding to voltage changes, which
correspond to the ones and zeros of binary
language. A high voltage indicates a one and
a low voltage a zero.
In order to recognise a one, the voltage has
to ramp up sufficiently to land within a set
voltage range. However, if you overclock your
CPU’s frequency, the voltage may not be able
to climb quickly enough to reach that high
voltage range to represent a one and instead
is interpreted as a zero. This will cause an
error and is one reason your PC will become
unstable when overclocked.
By increasing the CPU voltage or vcore,
you can help increase the rate at which the
switching voltage ramps up, allowing it to
respond in time to keep up with the clock
frequency. There are limits to how far you can
push this though. The first limitation is that
increasing the vcore increases the power being
pumped into the CPU, resulting in more waste
heat, and even though your cooling systemmay be able to keep up, internally the CPU
might not. There can also be voltage leakage
and eventually, combined with the heat,
your CPU will start to scale poorly with more
voltage and eventually you won’t be able to
push it any further.THE EFI
Some of you reading this may remember the
traditional BIOS – a blue screen with white or
yellow text, where you may have spent hours
tweaking settings using keyboard navigation
only. This was replaced over a decade ago by the
Unified Extensible Firmware Interface, known
to enthusiasts as the EFI. This allowed larger
hard disks to be used, but also provided a much
more user-friendly interface for overclocking
and even offered slick, graphical interfaces for
controlling fan speeds. In this article, the EFI is
your one-stop-shop for overclocking and it’s
where you’ll find all the necessary tools for
setting frequencies and voltages.
To get into your motherboard’s EFI, you need
to tap the ‘Del’ key on your keyboard as soon as
you see a display on your screen. This will bring
up your EFI’s front page and from here you
can find the necessary sections to locate the
overclocking settings. It’s worth pointing out
that plenty of people still refer to the EFI as the
BIOS, and even motherboard manufacturers
will still offer ‘BIOS’ updates. They’re one and
the same thing.RYZEN MASTER
AMD’s Ryzen Master software can’t
be used for a 24/7 overclock and it can
be a bit of resource hog, but it’s still a
useful tool for applying and testing
an overclock from the comfort of the
desktop, before applying in the EFI for
something more permanent. We’ll
be using it here to gauge our Ryzen 5
3600 overclock settings and you can
download it from amd.com