Thoughts and Comparisons

Throughout AMD's road to releasing details on Zen, we have had a chance to examine the information on the microarchitecture often earlier than we had expected to each point in the Zen design/launch cycle. Part of this is due to the fact that internally, AMD is very proud of their design, but some extra details (such as the extent of XFR, or the size of the micro-op cache), AMD has held close to its chest until the actual launch. With the data we have at hand, we can fill out a lot of information for a direct comparison chart to AMD’s last product and Intel’s current offerings.

CPU uArch Comparison
  AMD Intel
  Zen
8C/16T
2017
Bulldozer
4M / 8T
2010
Skylake
Kaby Lake
4C / 8T
2015/7
Broadwell
8C / 16T
2014
L1-I Size 64KB/core 64KB/module 32KB/core 32KB/core
L1-I Assoc 4-way 2-way 8-way 8-way
L1-D Size 32KB/core 16KB/thread 32KB/core 32KB/core
L1-D Assoc 8-way 4-way 8-way 8-way
L2 Size 512KB/core 1MB/thread 256KB/core 256KB/core
L2 Assoc 8-way 16-way 4-way 8-way
L3 Size 2MB/core 1MB/thread >2MB/cire 1.5-3MB/core
L3 Assoc 16-way 64-way 16-way 16/20-way
L3 Type Victim Victim Write-back Write-back
L0 ITLB Entry 8 - - -
L0 ITLB Assoc ? - - -
L1 ITLB Entry 64 72 128 128
L1 ITLB Assoc ? Full 8-way 4-way
L2 ITLB Entry 512 512 1536 1536
L2 ITLB Assoc ? 4-way 12-way 4-way
L1 DTLB Entry 64 32 64 64
L1 DTLB Assoc ? Full 4-way 4-way
L2 DTLB Entry 1536 1024 - -
L2 DTLB Assoc ? 8-way - -
Decode 4 uops/cycle 4 Mops/cycle 5 uops/cycle 4 uops/cycle
uOp Cache Size 2048 - 1536 1536
uOp Cache Assoc ? - 8-way 8-way
uOp Queue Size ? - 128 64
Dispatch / cycle 6 uops/cycle 4 Mops/cycle 6 uops/cycle 4 uops/cycle
INT Registers 168 160 180 168
FP Registers 160 96 168 168
Retire Queue 192 128 224 192
Retire Rate 8/cycle 4/cycle 8/cycle 4/cycle
Load Queue 72 40 72 72
Store Queue 44 24 56 42
ALU 4 2 4 4
AGU 2 2 2+2 2+2
FMAC 2x128-bit 2x128-bit
2x MMX 128-bit
2x256-bit 2x256-bit

Bulldozer uses AMD-coined macro-ops, or Mops, which are internal fixed length instructions and can account for 3 smaller ops. These AMD Mops are different to Intel's 'macro-ops', which are variable length and different to Intel's 'micro-ops', which are simpler and fixed-length.

Excavator has a number of improvements over Bulldozer, such as a larger L1-D cache and a 768-entry L1 BTB size, however we were never given a full run-down of the core in a similar fashion and no high-end desktop version of Excavator will be made.

This isn’t an exhaustive list of all features (thanks to CPU WorldReal World Tech and WikiChip for filling in some blanks) by any means, and doesn’t paint the whole story. For example, on the power side of the equation, AMD is stating that it has the ability to clock gate parts of the core and CCX that are not required to save power, and the L3 runs on its own clock domain shared across the cores. Or the latency to run certain operations, which is critical for workflow if a MUL operation takes 3, 4 or 5 cycles to complete. We have been told that the FPU load is two cycles quicker, which is something. The latency in the caches is also going to feature heavily in performance, and all we are told at this point is that L2 and L3 are lower latency than previous designs.

A number of these features we’ve already seen on Intel x86 CPUs, such as move elimination to reduce power, or the micro-op cache. The micro-op cache is a piece of the puzzle we wanted to know more about from day one, especially the rate at which we get cache hits for a given workload. Also, the use of new instructions will adjust a number of workloads that rely on them. Some users will lament the lack of true single-instruction AVX-2 support, however I suspect AMD would argue that the die area cost might be excessive at this time. That’s not to say AMD won’t support it in the future – we were told quite clearly that there were a number of features originally listed internally for Zen which didn’t make it, either due to time constraints or a lack of transistors.

We are told that AMD has a clear internal roadmap for CPU microarchitecture design over the next few generations. As long as we don’t stay for so long on 14nm similar to what we did at 28/32nm, with IO updates over the coming years, a competitive clock-for-clock product (even to Broadwell) with good efficiency will be a welcome return.

Power, Performance, and Pre-Fetch: AMD SenseMI Chipsets and Motherboards
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  • bobsta22 - Saturday, March 4, 2017 - link

    Office with 20 PCs - all developers - loads of VMs and containers.

    All the PCs are due a CPU/Gfx refresh, but ITX mobos required.

    Cant wait tbh. This is a game changer.
  • prisonerX - Saturday, March 4, 2017 - link

    What if they come out with a 16 core line next year!
  • bobsta22 - Saturday, March 4, 2017 - link

    What?
  • lilmoe - Tuesday, March 7, 2017 - link

    It really is. As a freelance developer, I can't wait.
  • ericgl21 - Saturday, March 4, 2017 - link

    For me, the more important thing to see from AMD is if they can come up with a chip that can beat the mobile Core i7-7820HQ (4c/8t no ECC) & the Xeon E3-1575M v5 (4c/8t with ECC), for less money.
    And the number of PCIe gen3 lanes is very important, especially with the rise of M.2 NVMe storage sticks.
  • cmagic - Sunday, March 5, 2017 - link

    Will anandtech review Ryzen in gaming? I would really like Anandtech view, since I don't really trust other sites especially those "entertainment" sites. Want to see how Anandtech dive into its main cause.
  • Tchamber - Sunday, March 5, 2017 - link

    @cmagic
    Page 15
    2017 GPU
    The bad news for our Ryzen review is that our new 2017 GPU testing stack not yet complete. We recieved our Ryzen CPU samples on February 21st, and tested in the hotel at the event for 6hr before flying back to Europe.

    I just ordered my 1700X, I plan to keep it for at least 5 years, as my needs don't change much. My current Intel 6 core is coming up on 7 years old now. I like to buy high end and use it a long time.
  • Lazlo Panaflex - Monday, March 6, 2017 - link

    Same here...probably gonna grab a 1700 at some point and put this here i5-2500 non-k in the kids computer.
  • asH98 - Sunday, March 5, 2017 - link

    '''The BIG QUESTION is WHY are the HEDT benchmarks (professional ie Blender) fairer than gaming benchmarks??

    Bottom line is that CUTTING-EDGE CODING is happening NOW in AI, HPC, data, and AV/AR, game coders because of $$$ are the last to change or learn unless forced (great for NVidia Intel) so most of the game coding is stuck in yesteryear- Bethesda will be the test bed for game coders to move forward
    Hence the difference in game benchmarks vs 'professional' (HEDT) benchmarks. Game coders can get stuck using yesterday's code without repercussions and consequences as long as old hardware dominates and there are no incentives to change or learn new skills. The same Cant happen in the Professional area where speed is tantamount to performance and $$$
  • TheJian - Sunday, March 5, 2017 - link

    I hope you're going to test a dozen games at 1080p where most of us run for article #2 and the GAMING article should come in a week not 1/2 year later like 1080/1070 gtx reviews...LOL. As this article just seems like AMD told you "guys, please don't run any games so we can sell some chips to suckers before they figure out games suck". And you listened. No point in testing 1440p or 4k for CPU, and 95% of us run 1920x1200 and BELOW so you should be testing your games there for a CPU test.

    The fact they are talking Zen2 instead of fixing Zen1 kind of makes me think most of the gaming is NOT going to be fixable.
    http://www.legitreviews.com/amd-ryzen-7-1800x-1700...
    149fps for 7700 in theif vs. 108 for 1800x? JEEZ. GTA5 again, 163 to 138. Deus ex MD 127 to 103. These are massive losses to Intel's chip and Deus was clearly gpu bound as many of Intel's chips hit the same 127fps including my old 4790k :( OUCH AMD.

    https://www.guru3d.com/articles_pages/amd_ryzen_7_...
    Tombraider same 7700k vs. 1800x 132fps to 114 (never mind 6850 scoring 140fps). This will probably get worse as we move to 1080ti, vega, nvidia refresh for xmas, Volta, 10nm etc. If you were using a faster gpu the cpus will separate even more especially if people are mostly gaming at 1080p. Even if many move to 1440p, that maybe fixes some games (tombraider is one with 1080 regular that hits a wall at 90fps), but again goes back to major losses as we move to 10nm etc. We get 10nm chips for mobile now and gpus probably next year at 12nm (real? fake 12nm? Either way) and might squeak into 2017 (volta, TSMC). 10nm gpus will likely come 2018 at the latest. Those gpus will make 1440p look like 1080p today surely and cpus will again spread out (and no, we won't all be running 4k then...LOL). You could see cpus smaller than 10nm BEFORE you upgrade your cpu again if you buy this year. That could get pretty ugly if the benchmarks around the web for gaming are not going to improve. One more point you'll likely be looking at GDDR6 (16Gbps probably) for vid cards allowing them to possibly stretch their legs even more if needed. Again, all not good for a gamer here IMHO.

    “But Senior Engineer Mike Clark says he knows where the easy gains are for Zen 2, and they're already working through the list”

    So maybe no fix in sight for Zen1? Just excuses like "run higher res, and code right guys"...I hope that isn't the best they've got. I could go on about games, but most should get the point. I was going to buy ryzen purely for Handbrake, but I'll need to see motherboard improvements and at least some movement on gaming VERY soon.

    One more ouch statement from pcper.
    https://www.pcper.com/news/Processors/AMD-responds...
    "For buyers today that are gaming at 1080p, the situation is likely to remain as we have presented it going forward."
    So they don't think a fix is coming based on AMD info and as noted as gpus get much faster (along with their memory speeds) expect 1440p to look like today's 1080p benchmarks at least to some extent.

    The board part is of major interest to me, so I can wait a bit and also see Intel's response. So AMD has be hanging for a bit here, but not for too long. I do like the pro side of these though (handbrake especially, just not quite enough).

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