
AMD Ryzen 3000 Post-Review BIOS Update Recap: Larger ST Gains, Some Gains/Losses - rbanffy
https://www.anandtech.com/show/14632/amd-ryzen-3000-review-bios-update-recap
======
mikedilger
I'd just like to say for anyone considering one of these new processors, there
are some downsides I wasn't expecting. Overall I'm fine with them, but
knowledge is power so here you go:

1\. RDRAND returns -1 (and sets the carry bit meaning it thinks -1 is a random
number). Supposedly this will be fixed in a BIOS update (which makes me think
it's an intended mode wrongly turned on... a backdoor?)

2\. On linux, CPU monitoring (e.g. temperature) is not available as AMD hasn't
published the specs on that yet

3\. While it has spectre "mitigations" (stibp, ibpb, ssbd), spectre is not yet
dead (spectre_v1, spectre_v2, spec_store_bypass).

4\. There is a bug/oddity in how it deals with %fs:
[https://www.phoronix.com/scan.php?page=news_item&px=DragonFl...](https://www.phoronix.com/scan.php?page=news_item&px=DragonFlyBSD)

5\. PSP/SEV ccp driver calls hang (on my machine at least, might be the mobo)
but luckily linux only waits a few seconds before giving up and continuing the
boot process.

6\. There have been reports of high idle voltages, but under linux w/o
monitoring I have no idea if I'm affected or if the issue is real or
significant.

For most use cases all of the above are minor and don't overshadow the price-
performance success of these processors.

~~~
Mirioron
> _1\. RDRAND returns -1 (and sets the carry bit meaning it thinks -1 is a
> random number). Supposedly this will be fixed in a BIOS update (which makes
> me think it 's an intended mode wrongly turned on... a backdoor?)_

Yet more evidence not to trust hardware random number generators.

~~~
userbinator
I'm very surprised that something like that even makes it into production.
You'd think processor manufacturers would have an extensive set of test cases,
at least one for each instruction...

I remember reading somewhere that, for a long time, Intel's "test cases"
basically consisted of all the operating systems they could find, going back
to MS-DOS 1.0 and including some more obscured ones, as well as tons of other
third-party software.

Unfortunately it seems this new generation no longer follows the "NEVER break
backwards compatibility" principle that made the PC such a great platform, and
as a result we're seeing hardware/software/firmware that's increasingly buggy
and divergent. It used to be the case that if a new processor couldn't run
existing software (even that which depended on undocumented but constant
behaviour) unmodified, it was a fatal flaw.

~~~
pjc50
Everything on a CPU is subject to heavy validation .. but I bet the random
number generator is exempt, because by definition it's not deterministic. It's
more like a peripheral "listening" to randomness.

[https://www.amd.com/system/files/TechDocs/amd-random-
number-...](https://www.amd.com/system/files/TechDocs/amd-random-number-
generator.pdf)

> "The RNG uses 16 separate ring oscillator chains as a noise source. Each
> chain consists of a different prime number of inverters in a free-running
> configuration which capture natural clock jitter"

So it's (deliberately) dependent on natural manufacturing variation in the
silicon, and in any deterministic simulator won't produce random numbers. It
also takes a while to start; it's possible that the startup conditions are bad
such that "a while" turns out to be "forever".

~~~
mulmen
Probably still worth checking that it doesn't return -1 every time.

~~~
NullPrefix
Infinity of -1's is a valid random sequence, just saying.

------
topspin
Those are significant single thread gains. It is concerning to me that BIOS
firmware has such a large influence over CPU performance. Buy from motherboard
manufacturers that are known to emphasize BIOS quality and performance.

There was also more performance left on the table in the initial AnandTech
tests on 7/7; conservative DDR-3200 JEDEC memory timing was used throughout.
More aggressive memory profiles will improve performance and AMD CPUs are
known to benefit greatly from better RAM performance.

So despite the already good results of Ryzen Gen 3 we can expect better
performance as the platform is optimized.

~~~
jl6
> Buy from motherboard manufacturers that are known to emphasize BIOS quality
> and performance.

Any suggestions, and reasoning why?

~~~
chronogram
They just wrote the reasoning why: because the firmware affects the system so
much.

As for the suggestion, that’s what I’ve been struggling with too. The gaming
motherboards popular for self assembly seem to be getting better at updating
the bios, but the manuals I’ve read still recommend against updating the
firmware. Which makes me guess you’d want to wait for the PlayStation 5 or the
next Xbox, or a PC vendor that is associated with fwupd, as that’s likely a
good indicator that they care about firmware.

~~~
jl6
Sorry, by reasoning I meant the reason why you consider a particular vendor
worthy of being associated with quality and performance. The internet
currently seems lacking in anything approaching a longitudinal study of
hardware vendors - it’s all a sea of opinions.

------
m0zg
Eagerly awaiting 3-rd gen Threadripper. That CPU will completely obliterate
Intel in the HEDT/Workstation market. Best I can tell, short of moving AVX512
(along with, e.g. VNNI) into their HEDT chips (which is not going to happen),
Intel has nothing to counter this threat.

~~~
wmf
Skylake-X already has AVX512 and Cascade Lake-X will have VNNI. Few
workstation apps use them, though.

~~~
m0zg
Looks like you're right. The pricing on those chips is pretty outrageous at
the moment though.

MKL and MKL-DNN take advantage of AVX512 and VNNI automatically, if available.
Lots of scientific software (basically all of it that cares about CPU perf)
use MKL and MKL-DNN.

~~~
kllrnohj
Simply having AVX512 support doesn't really tell you the whole story, though.
You'd want to actually benchmark it and see how much it's helping and then how
it compares to the competition. AVX512 comes with an insane clock speed
penalty, so while it can still put up some really impressive numbers, mixed
workloads can also end up not any faster (or even slower).

~~~
marmaduke
Yep I've heard this as well. More often than not it's faster to avoid AVX512
on recent Xeons. I don't think the same is true for Xeon Phi but those are
going away.

------
Havoc
What's with all that crap they stuck on the board. You can practically get a
epileptic fit from it.

~~~
grenoire
It's practically impossible to get a consumer motherboard without LEDs and
huge chunks of milled aluminium on it. Don't get it either...

~~~
towb
Was looking into building a new computer today, after 5 years with my current
one... Saw that even the ram sticks comes with leds. I don't want a single
light anywhere but that's not going to happen ¯\\_(ツ)_/¯

~~~
vbezhenar
Why do you care? Those lights are inside case. If you don't get case with
glass, you won't ever see it.

~~~
grenoire
It's a waste of metal, plastic, and electricity. Useless on _every single_
aspect you can think of, except for the hardcore gamer pandering bullshit.

~~~
vikramkr
I mean, it's not wasting that much of any of those. It's probably less
wasteful to just put LEDs on all those motherboards than create separate
product lines with and without the flair - if some decent majority of the
kinds of people that build their own PCs (gamers) want them, then it's easier
to save on all the tooling and design and so on to create a new "pro" line of
motherboards just for the people that don't want LEDs when they can just use
an opaque case.

~~~
shrimp_emoji
It wastes a lot! Unintuitively, for the things that do all the heavy lifting,
chips are incredibly power-efficient. The stuff on the side, anything that
glows or moves (LEDs and fans) takes up a disproportionate ton of power.

I don't like that X570 needs a chipset fan, but at least cooling's useful. I
can't have as much charity toward LEDs. Although I do like 'em. The æsthetic
is sick. Although not this one: [https://smile.amazon.com/G-Skill-
Trident-3600Mhz-PC4-28800-C...](https://smile.amazon.com/G-Skill-
Trident-3600Mhz-
PC4-28800-Channel/dp/B07M8YGCMV/ref=sr_1_2?keywords=Trident-Z+Royal+DDR4-3600&qid=1562984282&s=gateway&sr=8-2)

~~~
kllrnohj
> It wastes a lot! Unintuitively, for the things that do all the heavy
> lifting, chips are incredibly power-efficient. The stuff on the side,
> anything that glows or moves (LEDs and fans) takes up a disproportionate ton
> of power.

Not at all true. It's around 0.1-0.2 watt per LED. A RAM stick is going to
have maybe a dozen at most, so that's an extra 1-2 watts. Similar for a
motherboard. Maybe a fully binged out build is burning 10-20 watts on RGB,
give or take.

That's comparable to the power usage of just the VRMs or the X570 chipset
(which is 10-15w), to say nothing of the CPU or GPU itself (both of which
commonly blow past 100W under loads)

LEDs are very, very efficient. They do not take a "disproportionate ton of
power."

~~~
megous
2W is a power budget for an entire single borad computer I can run a desktop
on. So it's quite a lot in absolute terms for a led inside the case that I'll
never see.

10-20W is 10-40% of idle power consumption, perhaps, for a workstation. So it
wastes a lot even in relative terms.

~~~
kllrnohj
> So it's quite a lot in absolute terms for a led inside the case that I'll
> never see.

Then turn them off? The whole point of RGB lighting is it's controllable. That
includes setting it to off.

~~~
megous
Eh, point is 10-20W for a few blinkies is not efficient by any means.

~~~
kllrnohj
You missed the "fully blinged out" part. If you just get RGB on the
motherboard and RAM, the harder ones to avoid, it's going to well under 5W.
More like 2W. This is a power cost that basically doesn't exist in the context
of the entire system.

------
jtl999
How's the ECC RAM support with the 3000 series?

~~~
kllrnohj
Like previous Ryzen lineups the entire line has unbuffered ECC support.
Whether or not it's officially supported will depend most on the motherboard &
bios and if they tested & validated it.

At this point the Asus Pro WS X570-Ace (
[https://www.asus.com/Motherboards/Pro-
WS-X570-ACE/](https://www.asus.com/Motherboards/Pro-WS-X570-ACE/) ) appears to
be the only x570 board with certified ECC support.

~~~
JaimeThompson
How long will Asus keep updating that board with firwmare updates? In my
experience Asus is horrible about releasing updates after a couple of years.

~~~
kllrnohj
Asus is generally pretty good at updating the BIOS. My Asus X370-F gaming has
already been updated with support for Ryzen 3rd gen.

~~~
JaimeThompson
I have multiple Kaby Lake boards which haven't received any BIOS updates in >
a year. It depends upon the model line and as far as I can tell they will not
tell you how long support is before you buy one.

~~~
kllrnohj
What are you expecting an updated BIOS to do for that platform? Kaby Lake was
the last CPU line for that chipset series since Coffee Lake shuffled some pins
around. So what are you wanting updated that Asus hasn't provided?

~~~
JaimeThompson
There are issues with the BIOS on on of the systems randomly changing the m.2
PCIe speed between 4x and 2x. It only exists in the most current version of
the BIOS but doesn't happen on older version.

Their are also other issues that should be fixed but haven't.

------
shmerl
They are just firmwares today, not BIOSes, right?

I'm still waiting for the fix to be pushed for rdrand issue that breaks
systemd.

------
abductee_hg
the thing I'd like to see: implementations in "ispc vs asm vs intrinsics_msvc
vs intrinsics_clang vs intrinsics_gcc" on Intel and AMD CPUs. those "quake has
now 300 FPS" things tell me exactly nothing. (read: i am more interrested in
testing new features)

------
harry8
What's the inter thread latency, ie between cores on these beasts?

~~~
lhl
Here's an inter-core latency chart that includes both the 8 and 12 core Zen
2's as well as a comparison a comparison w/ Zen+ and Intel's latest (CFL-R):
[https://www.reddit.com/r/Amd/comments/calue1/intercore_data_...](https://www.reddit.com/r/Amd/comments/calue1/intercore_data_latency/)

Intra-CCX latency is now awesome, and all inter-CCX (including intra-CCD)
latency is not bad (and goes through IF) - what's interesting is that intra vs
inter-CCD latency seems to be within a ns or two. Pretty impressive
(considering it needs to bounce through the cIOD)!

~~~
harry8
Thank you kindly!

