
AMD Announces Ryzen Update: Enables Memory Clocks Up to DDR4-4000 - jjuhl
http://www.anandtech.com/show/11447/amd-announces-ryzen-agesa-1006-update
======
julian_1
It looks like their Windows PSP drivers open ports on 0.0.0.0.
[https://www.reddit.com/r/Amd/comments/6dinzy/why_do_amds_psp...](https://www.reddit.com/r/Amd/comments/6dinzy/why_do_amds_psp_drivers_make_my_pc_publicly/).

Note that AMD' claim that it's only local loopback (127.0.0.1) has been
refuted by numerous comments, and without further reply from AMD.

Given AMD's refusal to work with libreboot, or document the on-die Arm cores
with DMA memory access, these processors should not be considered secure for
any layer 3 networking, financial or security related tasks.

~~~
zurn
Note to people who aren't running Windows: this is unrelated to the article,
which covers some interesting iommu virtualization and memory controller
improvements in the latest firmware updates.

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frou_dh
The eternal question with overclocking is... Which tests and for how long does
your system need to pass them for it to be deemed a 100% stable overclock? The
different PC enthusiast communities and even individual posters within them
all have different answers.

~~~
paulmd
If your system will handle 15-30m of Prime95 SmallFFT then you're pretty much
good to go. Prime95 is real sensitive to instability and odds are good that if
it's gonna crash it'll crash in the first 10 seconds.

Beyond that, just pick your burner application of choice and let it run for an
hour while you go watch a movie. The rest are all kinda interchangeable as far
as I'm concerned. Aida64 maybe?

(one note: I _would not_ leave Prime95 running for prolonged periods of time.
Modern CPUs are not designed for a program that is so small it fits into uop
cache and runs AVX nonstop. With a heavy overclock it can pull 300W+
(potentially above 400W) on HEDT processors and OEMs like Asus have warned
that it may cause damage[0]. Electromigration seems like a likely culprit
meaning time is a key factor. Running Prime95 for like a half hour is fine and
a great stability test, but 24H+ runs are extremely unnecessary and
potentially damaging.)

[0] [https://rog.asus.com/articles/overclocking/rog-
overclocking-...](https://rog.asus.com/articles/overclocking/rog-overclocking-
guide-core-for-5960x-5930k-5820k/)

(Note that while this article is regarding Haswell-E, the same logic really
applies to Broadwell-E as well as Ryzen 5 and 7. Running a processor at triple
its nominal TDP nonstop for a prolonged period with most of that power going
though a few specific execution units simply cannot be healthy for it.)

~~~
userbinator
_Modern CPUs are not designed for a program that is so small it fits into uop
cache and runs AVX nonstop._

This is a slippery slope towards CPUs which are only warranted to run certain
approved apps. Overclocking aside, I'd consider a CPU _broken_ if it can't run
any sequence of instructions 24/7 without damage at the stock speed and
voltage.

Besides, Prime95 isn't what I'd consider a pathological case anyway --- FFTs
are common in scientific computing and signal processing, and having a CPU
continuously perform them is not at all an unusual workload.

It somewhat reminds me of
[https://news.ycombinator.com/item?id=7205759](https://news.ycombinator.com/item?id=7205759)

~~~
eigenvector
I agree with you, but with the caveat that CPUs should be able to run flat-
out, indefinitely _at rated voltage_. In this case, people are over-volting
the CPU by up to 40% so running the hardest workloads simply pushes an amount
of power (heat) through the CPU that it was never intended to handle.

------
hammerandtongs
Uhoh this kind of removes one of the things holding me back from buying -

"""The last addition should excite those interested in virtualization. AMD has
announced "fresh support" for PCI Express Access Control Services (ACS), which
enables the ability to manually assign PCIe graphics cards within IOMMU
groups. This should be a breath of fresh air to those who have previously
tried to dedicate a GPU to a virtual machine on a Ryzen system, since it has
thus far been fraught with difficulties."""

People have been fairly successful over the years combining their windows
games box into their linux workstation by doing this.

I haven't dipped in but I am pretty tempted.

Can anyone comment on the stability of the linux workstation if the windows vm
takes a dump via bad drivers etc? That's my concern is that my linux
workstation is highly highly stable and I don't want to borrow problems just
to save a box.

~~~
kbwt
You might want to hold out until AMD gets the "Nested Page Tables" issue
fixed.

It's supposed to speed up virtual memory handling in the guest by avoiding the
need for shadow page tables and/or emulation by the host.

Currently the feature is broken, resulting in crippled GPU performance,
allegedly due to the IOMMU not keeping up with the DMA transaction rate. You
can disable it entirely (kernel command line amd-kvm.npt=0) at the cost of ~5x
increased CPU usage and constant stuttering in games, which is what most
people choose to do for now.

~~~
hammerandtongs
Hah!

Well that will help me push this project off for a few months more :)

Is there a good spot to keep up with this, that is very linux focused?

~~~
kbwt
[https://www.reddit.com/r/VFIO/](https://www.reddit.com/r/VFIO/) and
[https://www.redhat.com/archives/vfio-
users/](https://www.redhat.com/archives/vfio-users/)

~~~
hammerandtongs
Brilliant, thank you.

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jbmorgado
Just to be clear, does this solve the issues with GPU passthrough in
virtualization environments (i.e. KVM)?

~~~
kbwt
It seems like it will help if your motherboard doesn't already have convenient
IOMMU groupings.

There's nothing to indicate that this will help with the NPT issue, so expect
poor performance (CPU or GPU, your choice).

~~~
rrego
What is the NPT issue?

~~~
kbwt
I posted about it below:
[https://news.ycombinator.com/item?id=14427098](https://news.ycombinator.com/item?id=14427098)

There's also a thread on the vfio-users mailing list and on a few other
mailing lists as well as some discussion on /r/vfio.

------
fulafel
Can these AGESA firmware updates (or board specific firmware upgrades
incorporating the AGESA update) be installed from Linux? Is there a standard
UEFI method for it?

Edit: looks like you can do it inside the firmware GUI, no OS is required. You
can update over the net, or load update files from USB stick.

------
api
Does DDR4-4000 really mean that your RAM is now _very_ close to CPU core
speed? That could result in a massive performance boost for a lot of things.

~~~
ploxiln
Nope, DDR4-4000 is not "running at 4 GHz". SDRAM 133 ran at 133 MHz, but DDR
numbers have always multiplied their frequency by "number of simultaneous
transfers" or something like that. (The first DDR multiplied by two - "double
data rate".)

Wikipedia has a good table for DDR3:
[https://en.wikipedia.org/wiki/DDR3_SDRAM#JEDEC_standard_modu...](https://en.wikipedia.org/wiki/DDR3_SDRAM#JEDEC_standard_modules)

DDR3-2133 has a 266.67 MHz memory clock, and a 1066.67 MHz bus clock (x 4),
and a "data rate" of 2133 "mega-transfers per second". And a bunch of other
details, it's complicated.

The point is, don't take the "4000" literally. It's complicated. And timings
and latency can differ between models of the same "data rate".

------
IceyEC
Any word on ECC support for the Ryzen chips?

~~~
valarauca1
Ryzen will work with ECC ram but it won't actively correct ECC errors (at
least on Linux) the interrupt code flags that as _differed_.

Currently there aren't Ryzen server chips out, just desktop/enthusiast models.

~~~
deaddodo
Yes, it does. It'll correct 1-bit errors and report 2-bit errors. It just
doesn't fault on 2-bit errors, as is expected.

~~~
theevilsharpie
Ryzen will send a machine check exception to the OS in the event of a double-
bit error. It's up to the OS on how to handle it.

This also isn't a Ryzen-specific behavior. All x86 ECC-capable machines work
this way.

