L
et’s be honest, AMD’s 64-core Threadripper
3990X is so far outside the envelope for
most of us that it’s a desktop CPU in name
only. The high motherboard cost, eye-watering CPU price
and sheer number of cores mean this monster CPU is not only
out of reach for most of people, but completely unneeded too.
We already began to see the limits of standard Windows-
based desktop PCs with AMD’s Threadripper 3970X,
with diminishing returns in many benchmarks that simply
can’t scale to use so many cores. Throwing a 64-core
beast at them isn’t likely to improve the
situation, so while the Threadripper
3990X is undoubtedly a monster CPU, it’s
still a niche product that needs the right
conditions to show its true potential.
Its specs certainly pack a punch, though,
with a monumental 256MB L3 cache and
32MB L2 cache, thanks to all four Core Chiplet
Dies and their corresponding eight Core
Complexes being enabled. Despite this, AMD
maintains the same 280W TDP as the other
two 3rd-gen Threadripper CPUs, thanks to
lower boost frequencies.
Indeed, we observed an all-core boost
of 3.25GHz in Cinebench R20’s multi-
threaded test with our 240mm all-in-one
liquid cooler, but the 32-core Threadripper
3970X regularly hit 3.9GHz. As such, unless
all those cores are fully utilised, the cheaper
Threadrippers may end up being faster in
some lighter-threaded tests. The single-
core boost is also 200MHz lower than the
Threadripper 3950X, and our experience
with Precision Boost Overdrive and manual
overclocking Zen 2 CPUs is that it’s unlikely
you’ll attain a higher peak boost than that.Performance
At stock speed, our usual benchmarks failed
to respond to the extra cores, which is toAMD THREADRIPPER
3990X/ £3,530 inc VAT
SOCKET TRX4 CPU
be expected. There was little difference in our mostly single-
threaded GIMP image editing test between the 3990x and
the 3970X, although both chips still outperformed Intel’s Core
i9-10980XE here. The result from our multi-threaded video
encoding test was disappointing, but again, this is down to
HandBrake simply not utilising this many cores. In fact, even
Intel’s 18-core CPUs represent poor value here, even if they
show a little scaling. The system score in the end was similar to
other 3rd-gen Threadripper CPUs, so the 3990X won’t give you
much more performance in general mainstream use, if any.
We then used two versions of Blender in our testing, as the
latest version better supports high core-count CPUs. In version
2.79, the 3990X was only a couple of seconds quicker than
the 3970X, but in the newer version, it was 37 per cent faster,
showing much better scaling. Cinebench R20 also saw a
sizeable improvement, with 3970X’s 17,303 score eclipsed by
the 3990X’s 24,116.
Overclocking quickly results in a power supply-battering,
cooler-melting exercise, but ultimately our goal was to
improve that all-core boost frequency from 3.25GHz. Our
powerful EKWB Phoenix liquid cooler certainly helped,
as it meant that applying PBO and maximum automatic
overclocking settings in Ryzen Master saw the CPU hit
3.9GHz across all cores under load.
This saw the power draw rocket to 845W, but the Cinebench
score rose to a massive 28,432 and the Blender 2.82 result fell
from 31 seconds to just 24 seconds (although performance
massively dropped in Handbrake). The CPU regularly topped
80°C at these settings, though, so you’ll need monstrous
cooling for long load periods.Reviews
REVIEWS / PROCESSORS
SUPPLIER box. co. uk
SPEC
Base frequency
2.9GHz
Max boost frequency
4.3GHz
Core
Zen 2
Manufacturing process
7nm
Number of cores
64 x physical (128 threads)
IGP
None
Simultaneous Multithreading (SMT)
Ye s
Cache
256MB L3, 32MB L
Memory controller
Quad-channel DDR4, up to
3200MHz )
Packaging
AMD Socket TRX
Thermal design power (TDP)
280W
Features
Precision Boost 2, Precision Boost
Overdrive, FMA3, F16C, SHA, BMI /
BMI1 + BMI2, AVX2, AVX, AES, SSE4a,
SSE4, SSSE3, SSE3, SSE2, SSEcc
uuss
tommPP
CCP
R
O
FE
SSION
A
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