This created latency, meaning the CPU was severely held
back when it came to lightly threaded tasks, and even
some heavily multi-threaded tasks, with only a select few
workstation-class workloads that were largely unaffected
by the configuration being able to take full advantage of the
extra cores.
This meant that the 24 and 32-core CPUs were barely any
faster in some multi-threaded tasks than the Threadripper
2950X, which had half the number of cores.
Some of this performance drop was later found to be down
to the way Windows handled the CPU, but there’s still some
blame to be laid at the CPU itself.
AMD also tried to circumvent some of these issues with
Ryzen Master as well, as some games saw large performance
drops with the 24 and 32-core CPUs. The software allowed for
the disabling of cores, as well as switching between local and
distributed memory modes. It was all a bit involved.
This all changes with 3rd Gen Threadripper, though,
as AMD has tweaked the topology to allow each core to
access all four memory channels, and access the PCI-E
bus independently. There’s a pair of dual-channel memory
controllers, giving you four channels in total in the new CPUs,
and both controllers can be accessed at the same time by all
the CCDs via the I/O die. Both CPUs feature a quartet of 7nm
Core Chiplet Dies (CCDs), each with either six or eight active
cores. The CPU also sports a 12nm I/O die, which ties the
four CCDs together, connecting them to the PCI-E bus and
memory channels with Infinity Fabric.
AMD claims that this new design brings up to a 60 per cent
improvement in performance, thanks to the lower latency
and increased bandwidth, along with the proven benefits of
the Zen 2 architecture and improved memory speed support.
There is, of course, also PCI-E 4 support with Zen 2, and AMD
has increased the number of lanes to the CPU from four to
eight, with 72 total usable
PCI-E 4 lanes.
This equates to 112GB/
sec of concurrent PCI-E 4
bandwidth from the CPU’s
56 PCI-E lanes, and 16GB/
sec to and from the chipset.
AMD has also massively
expanded the on-board
cache amounts in much the
same way as its 3rd-gen
Ryzen CPUs. With double
the cores compared with
the Ryzen 9 3950X, you
get 128MB of L3 cache
and 16MB of L2 cache.
ANTONY LEATHERAMD has increased the number of lanes to the CPU from four to
eight, with a total of 72 usable PCI-E 4 lanes