Custom PC - UK (2020-07)

ANINTERVIEWWITH OVERCLOCKING CHAMPION 8PACK

Ian ‘8pack’Parry is a professional overclocker

and system builder for Overclockers UK

Asus, which is my motherboard of choice on

LGA2066, I boot with 1.1V SA and IO but tune the

IO down to 0.92V. Doing these small tweaks

saves 8-10°C, and don’t forget to apply an AVX

offset of minus three or four and even 11 or 12

with AVX512 to reduce its frequency a lot for

these workloads. This is even a tweak we do

this with customer systems.

What about AMD CPUs?

On Socket AM4, you need to benchmark and

overclock in your specific programs to see

if it helps. I’ve found that overclocking rarely

helps in lightly threaded applications as the

single core boosts are high on AMD CPUs, so

you’re usually better off using Precision Boost.

However, in multi-threaded applications, you

can easily gain 20 per cent performance using

a manual overclock. It’s worth looking at the

voltages Precision Boost is using too. I find that

a manual overclock can lower heat and power

consumption in multi-threaded workloads. On

Socket AM4, I’ll use around 1.35v maximum,

which is often less than PBO, so that can save

heat and temperatures under load. On Socket

TRX4 and Socket AM4, you can usually save

temperatures by tuning SOC voltages and

again lowering memory voltages.

What about memory overclocking

and frequencies?

With LGA115x, there’s very little difference above

3200MHz in real-world benchmarks, so adding

more heat by increasing voltages isn’t a good

idea. In fact, it’s worth lowering the DDR voltage

as much as possible. Many 3600MHz kits can

run at much lower voltages anyway. In any

event, I’d start by getting the most out of the CPU

core. Then I’d tune the cache or Infinity Fabric,

and the last thing would be memory. It’s always

a balancing act between different types of load,

so you need to work out what your priorities are

first. That’s how we tune systems for customers.

With AMD, 3600MHz, memory is usually

the best option, as most CPUs will do this linked

with Infinity Fabric. Occasionally I might reduce

the ratio to get a higher CPU frequency, but you

lose efficiency. Also with AMD, the main things

I tweak are loadline calibration to prevent droop

on both core and SOC. Also max out the power

and current limits where possible, but pushing

memory higher using the dividers doesn’t really

aid 24/7 or extreme overclocking.

In your experience, does spending more

on cooling on a home setup scale at all with

overclocks? For instance, going from mid-

range air to high-end air to high-end AIO then

DIY liquid cooling?

It depends on other limiting factors really. Right

now, with soldered heatspreaders, you can get

100-125MHz extra with good water cooling

compared with air and of course, it results in a

much quieter PC too.

The thermal paste Intel used for a while

was definitely a limiting factor. With AMD

mainstream CPUs, though, not so much. A lot

depends on workloads too. If you need good

AVX512 performance then on LGA2066, there’s

not a chance you can do that with air cooling.

This is why the best stability test for anyone’s

overclock is an actual workload.

S

ome of us are lucky enough to
overclock various systems on a
regular basis, but we chatted to
someone who does it on a daily
basis and in extreme ways too. Ian Parry, better
known as 8Pack, is one of the world’s best
overclockers and currently builds crazy PCs for
Overclockers UK. We caught up with him to get
his top tips on other settings you can tweak and
opinions on all things overclocking.

So Ian, what would be your top tips for the
various CPU sockets around at the moment
when it comes to overclocking?
I’d start by setting the XMP profile on the
memory in the EFI. Then I’d make sure the
board is setting correct voltages and timings
for the memory too. I’d also set a degree of
loadline calibration, so the voltage doesn’t
droop under load and cause instability. On
Intel CPUs, I’d max out the CPU and memory
current limits, as these can hinder even modest
overclocks on some boards. In addition, I’d also
max out the power limits.
From there, it can often be a case of lowering
some voltages to rein in temperatures. On all
Intel CPUs I save degrees of heat by tuning
down SA and IO voltages. With LGA115x, you
can also lower the memory voltage quite a bit,
usually to around 1.15-1.25V, especially with
3200MHz kits. Just this change can result in
between 5-10°C temperature savings.
On LGA115x, I also tune the cache to gain
further efficiency. All processors can do a x45
cache ratio, so start at that. Increasing the cache
ratio by two or three points is the same as
100MHz on the CPU, so it’s worth doing.
For gaming-only systems, I would disable
Hyper-Threading too. You can easily save up to
10°C under load and gain an extra 100MHz. If
you have a 6-core or 8-core CPU then Hyper-
Threading is probably not even helping in
games and can actually result in slower frame
rates in some. On LGA115x, you should apply
a -3 ratio for AVX workloads. They generate a
lot more heat, so you need to make sure your
overclock is stable if you deal with them.
On LGA2066, you can lower temperatures
again by tuning SA, IO and cache voltages. Once
you find these in the EFI, and once you have
a stable overclock, try to reduce them below
their stock settings. For example, 0.92V on
the cache voltage still allows for a x28 ratio. On

FEATURE / CUSTOMISATION