If you're watching this right now, you're probably using at least one arm
CPU to do it. Or well, not an arm CPU because arm doesn't actually make CPUs.
Or do they? That's the big news that they sponsored
us down here to their arm everywhere event to announce. Behind me and in my
hand is the arm AGI CPU built for
performance, scale, and as always
efficiency. Up to 136 arm Neoverse V3 cores with 2 megabytes
of level 2 cache each built on TSMC's 3
nanometer process node, and they can run at up to 3.6 GHz, which
right out of the gate raises some questions, doesn't it? Just 3.6 GHz? Can
it like dynamically boost a single core way higher or something?
No. And according to arm, that's
actually a key feature, not a bug. By eschewing SMT multithreading and the
highly variable power consumption that's associated with constantly fluctuating
clock speeds, not to mention designing a 12-channel DDR5 memory controller that
can feed every individual core with a consistent 6 GB/s of bandwidth, arm is
ensuring that every core in the CPU will perform its best at all times and keep
power consumption more consistent, which will allow data centers to design to how
much power their racks will consistently consume rather than having to build in a
buffer for how much they might consume at peak.
And that's huge considering that cooling and especially power are just about the
hottest commodities in a world that is rapidly scaling data center
infrastructure. Each AGI CPU has 96
lanes of PCI Express Gen 6 with support for CXL 3.0 for deploying massive shared
memory pools over PCIe, and arm showed
off node designs with their hardware partners that deployed up to two of
these CPUs on a single motherboard.
Super cool, but not exactly world-changing
yet. To see the vision that led Arm to spend
the last few years bringing this to life, you got to zoom out and look beyond the individual node to the rack
level. This rack contains 32-node
1P servers. So, for those keeping count at home, that's 8,160
CPU cores. Okay, still not that big of a deal. I
mean, dense CPU racks are already a thing.
Well, here comes the big reveal. This sick error message hoodie is now
available from lttstore.com. JK, okay. I mean, it is, but that's not
the big reveal. The big reveal is that everything that I just told you fits in
a standard OCP 36 kW air-cooled rack.
Each AGI CPU draws just 300 W,
a significant reduction compared to flagship x86 CPUs. So, when you throw
liquid cooling at them, the numbers get frankly kind of ridiculous. In an OCP
200 kW rack, Arm figures they can pack
42 eight-node 1P systems for a grand
total of 45,696
cores and over a petabyte of RAM, all while consuming only about half of that
total available power budget. They are pegging the bottom line
performance per watt in the neighborhood of double compared to x86. And this is
largely thanks to carrying less legacy cruft, but also thanks to architectural
choices like using fewer chiplets to keep memory latency down, along with
Arm's traditional strength in instructions per clock, and taking just
a no silicon wasted approach to their design. With the cost and scarcity of power,
that's a number that is going to perk up a a of ears. But, why though? Everybody
knows that CPUs aren't good at AI compared to GPUs or application specific
neural processors. So, uh what's with the branding?
Arm met that question head-on. While GPUs and neural accelerators get
all the attention, CPUs are still chugging along in the background
coordinating tasks with Arm estimating that a typical deployment today is going
to have about 30 million cores per gigawatt.
But, here's the thing. That's with humans handling most of the token
requests. AI agents push requests much faster and
um don't sleep. Meaning that your expensive
AI accelerators can end up sitting around because the CPU coordinators
can't keep up with all of those requests.
So, Arm figures that that 30 million cores per gigawatt number could go up a
lot in head node next to the accelerator
rack as high as about four times as many. But, uh here's the thing. When
these are doing all the actual AI work, nobody's going to want to spend more
power budget on all of those CPUs.
Well, that's where Arm comes in with their
famously power efficient designs. Let's go to Nick from the lab to see
this thing in action. Many of the demos were focused on the ease of porting
software to Arm and the support they're building for developers, which makes a
lot of sense, but isn't very visual. So, let's check out this one instead where
they're encoding a 1080p video from H.264 to H.265 while running computer
vision at the same time on the same CPU. Let's go take a look at the man behind
the curtain. That's not a video recording. Arm actually had the stones
to do it live bringing an actual server
running the actual hardware here to the show floor. But, um
awkward question. Doesn't all of this put Arm kind of in direct competition
with their own customers? You know, the ones who license their IP and their
compute subsystems, the guys who got them where they are today? Well, on
paper, yes, um absolutely.
But, from ARM's perspective, this is actually something that many of their
customers were asking for. Expanding on that, ARM laid out how their road map
and their policies account for how all three of their business models are going
to go forward. And they're positioning this as a choice between IP licensing,
compute subsystems licensing, and physical CPUs, or hey,
why not some combination of all three? They'll gladly take your money any way
you want to give it to them. Contact your local sales representative.
Will is here. He can be reached afterwards. And it
seems like that's the plan for the long haul. In a move that I don't think I've
ever seen before, ARM stood up on stage and said the quiet part out loud, "This
is just a safe first attempt. The best is yet to come with our second CPU due
next year." Like, obviously, given the timelines of
silicon development, but you almost never hear that from a company who
probably wants you to buy the hardware they have today from partners like, you
know, for example, Supermicro. Pretty wild.
If you guys enjoyed this video, you might enjoy the one that we did at CES,
also in partnership with ARM, highlighting some of the unexpected
places that you can find ARM technology.