AMD Zen Microarchitecture: Dual Schedulers, Micro-Op Cache and Memory Hierarchy Revealed
by Ian Cutress on August 18, 2016 9:00 AM ESTSimultaneous Multi-Threading
On Zen, each core will be able to support two threads in what is called ‘simulatenous multi-threading’. Intel has supported their version of SMT for a number of years, and other CPU manufacturers like IBM support up to 8 threads per core on their POWER8 platform designs. Building a core to be able to use multiple threads can be tough, as it requires a lot of resources to make sure that the threads do not block each other by consuming all the cache and buffers in play. But AMD will equip Zen with SMT which means we will see 8C/16T parts hitting the market.
Unlike Bulldozer, where having a shared FP unit between two threads was an issue for floating point performance, Zen’s design is more akin to Intel’s in that each thread will appear as an independent core and there is not that resource limitation that BD had. With sufficient resources, SMT will allow the core instructions per clock to improve, however it will be interesting to see what workloads will benefit and which ones will not.
Timeframe and Availability
At the presentation, it was given that Zen will be available in volume in 2017. As the AM4 platform will share a socket with Bristol Ridge, users are likely to see Bristol Ridge systems from AMD’s main OEM partners, like Dell and others, enter the market before separate Zen CPUs will hit the market for DIY builders. It’s a matter of principle that almost no consumer focused semiconductor company releases a product for the sale season, and Q1 features such events as CES, which gives a pretty clear indication of when we can expect to get our hands on one.
It’s worth noting that AMD said that as we get closer to launch, further details will come as well as deeper information about the design. It was also mentioned that the marketing strategy is also currently being determined, such that Zen may not actually be the retail product name for the line of processors (we already have Summit Ridge as the platform codename, but that could change for retail as well).
Wrap Up
AMD has gone much further into their core design than I expected this week. When we were told we had a briefing, and there were 200-odd press and analysts in the room, I was expecting to hear some high level puff about the brand and a reiteration of their commitment to the high end. To actually get some slides detailing parts of the microarchitecture, even at a basic cache level, was quite surprising and it somewhat means that AMD might have stolen the show with the news this week.
We’ve got another couple of pieces detailing some of the AMD internal/live benchmark numbers during the presentation, as well as the dual socket server platform, the 32-core Naples server CPU, and what we saw at the event in terms of motherboard design.
Facebook
Twitter
RSS
216 Comments
View All Comments
Kevin G - Saturday, August 20, 2016 - link
HyperTransport was an AMD creation though they were not the first to use it. Former DEC engineers did help create it but they were employees by AMD at the time. AMD did license the EV6 bus for the the first Athlon (not Athlon 64). The first chip to that used the HT bus was Transmeta due to delays on the first generation Athlon 64/Operton.slyronit - Tuesday, August 23, 2016 - link
Ah! Good old days! I used to read all this in "Chip" magazine back in the day. Cyber cafes those days used "Cyrix" CPUs. Cheap.BMNify - Friday, August 19, 2016 - link
thats the thing, Did AMD actually learn something from their ARM inc partners and put in a real up to date interconnect or two that can lower overall latency and massively improve data throughput (ready with HBM2 perhaps) or did they cheap out again and rehash the usual antiquated suspectsnandnandnand - Thursday, August 18, 2016 - link
Good. I want Zen to perform well. Let's see Intel copy AMD and offer a 8c/16t chip at mainstream prices.akamateau - Thursday, August 18, 2016 - link
Hmmm...AMD was first with 1Ghz and faster processors.
AMD was first with multi-core processor.
AMD was first with CPU + GPU = APU. Intel has the laughably poor performing Intel IGP LOL. And to get it Intle had to poach technology from NVidia and then NVidia sued them!!!! LOL
AMD owns X86-64.
SO your point?????
AMD has a license to copy Intel and if like Frank Sinatra chooses to do it their way, it can only be good for the consumer.
So smarten up. Without AMD Intel would have killed the PC 10 years ago with $2000 CPU's!!!
smilingcrow - Thursday, August 18, 2016 - link
I don't live in the past from a decade ago. When AMD finally release their first decent CPU in 10 years wake me up.Even with negligible competition from AMD Intel has chosen to keep the prices of chips for the mainstream socket at low levels for 10 years. It was 2009 with Lynnfield that they last had a $1,000 Extreme chip for consumers and there were plenty of good chips in that range starting at under $300 so the Extreme chips were for rich fools really.
The_Countess - Saturday, August 20, 2016 - link
intel created a entire artificial market segment with the i5's because of lack of competition. they still sell dual cores for christ sake, and havent offered anything above 4 cores on the main stream market, which AMD's had for over 6 years already.On 22nm, let alone 14, there is no way they couldn't have made a affordable 6 core. but all we get are ridiculously priced -E variants on a ridiculously overpriced platform.
FMinus - Thursday, August 18, 2016 - link
that is still at most ~20 years back, AMD is on the face of the earth for 47 years and more as half of that they spend innovating nothing, but being contractors and priates of technology.tamalero - Friday, August 19, 2016 - link
whats with hardcore intel fanboys just getting out of their caves now that AMD might have a decent cpu to compete with Intel?The_Countess - Saturday, August 20, 2016 - link
and they went from that to creating the athlon64 and royally kicking intel's ass with superior innovations in just 14 years (counting from the first k5).to bad intel's monopoly abuse has already done its damage leaving AMD wofully short on production capacity meaning 80% of people still had to buy intel's crummy shit for too much money. and with AMD not making nearly as much money as it should have from the athlon64, intel could one again copy everything AMD did and then brute force outspend them.