Do Dual CPU Sockets Matter in 2018?
Linus Tech Tips
·Linus Tech Tips
·2019-05-06
·
1,284 words · ~6 min read
0:00
Zeon W,
0:05
Zeon scalable.
0:08
You know, they're both called Xeon,
0:12
but these things are really different.
0:16
One of them is basically a Core i9 with
0:20
ECC memory support and the other one is
0:24
a server CPU that I fanled all over
0:29
because I love super high-end expensive
0:32
tech toys. Now, in the past, you needed multiple
0:38
CPUs in one multi-socketed motherboard
0:43
in order to handle intensive multi-threaded workloads. But is that
0:48
still the case today? Do you still need
0:52
two of these given that a single Xeon
0:55
Platinum 8180 is 28 cores and 56 threads
1:02
on a single chip? Well, I don't know
1:06
what is the purpose today of a dual
1:09
socket machine like this one and how much have single high core count CPUs
1:16
eroded the market that they used to enjoy? Let's find out, shall we?
1:31
All right, there's a lot more room down here and we are going to need it for
1:35
this honking, not to mention heavy test bench. On this
1:40
test bench, you will find the ASUS C621E
1:44
Sage. This is a dual socket motherboard
1:48
rocking two LGA 3647 sockets for Intel's
1:54
Xeon scalable lineup of CPUs. And setups
1:59
like this have actually been around as far back as the 486 in 1989
2:06
with the resulting secondhand hardware giving enthusiasts the ability to get
2:11
multiple physical cores in their homes
2:14
over the years with the peak being somewhere in the mid 2000s or so. But
2:21
that was then and this is now. Now you
2:25
can get multiple processing cores in a
2:28
single chip. So
2:32
to see how far things have come, what we're going to do is pit this machine
2:38
against the fastest single CPU that
2:41
we've tested to date. We're going to try to keep the number of variables to a
2:46
minimum in order to gauge the impact that these extra CPU cores will have on
2:51
our setup. Though, it should be noted that there aren't many options when it
2:56
comes to aftermarket LGA3647
2:59
coolers because most of the folks
3:02
selling these kinds of systems would figure out their own solution. So, that
3:07
means that our dual socket workstation will run a little bit toasty, but we
3:11
didn't observe any thermal throttling, so it shouldn't affect our performance.
3:16
Let's start off then with good oldfashioned
3:19
Cinebench. I mean, we've we've seen this run before, but it's always fun to see
3:25
it finish that quickly.
3:31
So, in a surprise to no one, the dual
3:34
socket machine is faster. But
3:38
considering its 56
3:41
processing cores, not all of our workloads scale in the way that we might
3:48
expect. 7zip, for example, shows a
3:51
smaller thanex expected gain over our Core i9 Extreme Edition, and YC Cruncher
3:57
even finds itself losing ground. ASUS
4:00
Realbench demonstrates this, though, with that said, the encoding benchmark
4:05
ees out a lead over our Core i9 7980XE.
4:08
and then Blender. Well, here we actually get a victory for our dual CPU system
4:14
again, showing this platform's potential
4:17
for expanding render farms.
4:21
But what is really going on here? Well,
4:27
something you guys have to realize is that there is more to a dual socket
4:33
configuration than just more cores. Do
4:37
you remember when AMD managed a 3%
4:40
improvement in IPC with second gen Ryzen
4:44
just by improving cache latency? So on
4:47
this motherboard, we've got two separate CPUs with two separate sets of cache and
4:56
memory. See, these six banks go to this
4:59
one and these six banks are wired into this one. And that means a lot of
5:04
latency for compute tasks that require
5:07
the same data sets. This latency is a
5:11
necessary evil in the design of multiprocessor systems because of the
5:15
need for nonuniform memory access or
5:18
NUMA for short that allows these two
5:22
processors to efficiently share resources or as efficiently as they can.
5:27
So the short version of this is that it works by transparently allocating
5:31
devices and memory to each CPU which means they can more easily avoid
5:36
interrupting each other while accessing those resources. This in turn reduces
5:41
the amount of waiting around that they have to do for those resources to become
5:45
available. So that's what we're seeing during our testing like in Yunchruncher
5:51
for example where both CPUs are working
5:54
on the same data but it's not really the
5:57
intended use case for this kind of thing. What if we could use different
6:02
data sets? Then we should be able to find this kind of setups true calling.
6:08
And how better to do that than to effectively turn this system into two
6:14
independent computing machines using virtualization. So let's fire up on
6:20
which uses Red Hat KVM as a hypervisor
6:23
to see what kind of results we get splitting these resources into multiple
6:29
independent machines. Immediately, we
6:33
see worse results from our VMs than our
6:36
original 56 core testing.
6:40
But look closer at how much lower it is.
6:45
It's not a whole lot. In every test,
6:49
it's basically the same story here. And we are still way out ahead of the Core
6:55
i9 Extreme Edition, particularly when it comes to Blender. Now if we consider the
7:01
fact that we are getting simultaneous
7:04
work done that gives us a good look at
7:07
what an optimized workload might look like. I mean or heck uh virtualization
7:13
itself is a legitimate task too. I mean
7:16
this thing could be so many gamers in
7:20
one PC. But I digress. I mean, nobody is going
7:24
to buy something like this for their personal rig anytime soon, given the
7:29
$10,000 per CPU price tag, which puts it
7:35
squarely in the territory of big the
7:39
size of the check doesn't matter business. What they care about is
7:43
density. The more processing power a
7:47
single computer can manage, the more processing power that can be physically
7:52
fit into a building. And this is perhaps most important for data centers and
7:58
render farms in particular. The less those guys have to spend on setting up
8:03
the electricity and cooling management
8:07
for a data center versus the amount of
8:10
performance they can get, the better.
8:14
So, will multiple sockets make a comeback in
8:18
the proumer space? Outside of, you know, oil and gas
8:23
exploration where there are still workloads that can benefit from this
8:28
kind of thing, the chances look pretty slim if you ask me. But I don't
8:35
necessarily think that it's Intel's intent to sell these chips in the
8:39
proumer space. And for that matter, even
8:42
in the enterprise space, I don't think they move a ton of them. For me, I look
8:48
at a product like this as more of like a a future crafting exercise where it is
8:54
available today, but it's more of a representation of what actually might be
8:59
attainable a generation or two from now,
9:02
just like the 22 core processors that we were playing around with a couple of
9:07
years ago. Nowadays, those are much more
9:10
affordable and businesses are using them to power your cloud computing services.
9:17
So, thanks for watching, guys. If this video sucked, you know what to do. But
9:20
if it was awesome, get subscribed, hit that like button, or check out the link
9:24
to where to buy the stuff we featured in the video description. Also, linked down
9:27
there is our merch store, which has cool shirts like this one, and our community
9:31
forum, which you should totally join. Now I'm off to finally put this to use
9:37
for the reason that I obtained it.
9:41
Many video editors, one CPU.