The AMD Zen and Ryzen 7 Review: A Deep Dive on 1800X, 1700X and 1700
by Ian Cutress on March 2, 2017 9:00 AM ESTThoughts 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 World, Real 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.
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mapesdhs - Thursday, March 2, 2017 - link
It would be bizarre if they weren't clocked a lot higher, since there'll be a greater thermal limit per core, which is why the 4820K is such a fun CPU (high-TDP socket, 40 PCIe lanes, but only 4 cores so oc'ing isn't really limited by thermals compared to 6-core SB-E/IB-E) that can beat the 5820K in some cases (multi-GPU/compute).Meteor2 - Friday, March 3, 2017 - link
...Silverblue, look at the PDF opening test. What comes top? It's not an AMD chip.Cooe - Sunday, February 28, 2021 - link
Lol, because opening PDF's is where people need/will notice more performance? -_-CPU's have been able to open up PDF's fast enough to be irrelevant since around the turn of the century...
rarson - Thursday, March 2, 2017 - link
"AMD really isn't offering anything much for the mid range or regular desktop user either."So I'd HIGHLY recommend you wait 3 months, or overpay for Intel stuff. Because the lower-core Zen chips will no doubt provide the same performance-per-dollar that the high-end Ryzen chips are offering right now.
rarson - Thursday, March 2, 2017 - link
"their $499 CPU is often beaten by an i3."It's clear that you're looking at raw benchmark numbers and not real-world performance for what the chip is designed. If all you need is i3 performance, then why the hell are you looking at an 8-core processor that runs $329 or more?
Ratman6161 - Friday, March 3, 2017 - link
Its all academic to me. As I posted elsewhere, my i7-2600K is still offering me all the performance I need. So I'm just reading this out of curiosity. I also really, really want to like AMD CPU's because I still have a lot of nostalgia for the good old days of the Athlon 64 - when AMD was actually beating Intel in both performance and price. And sometimes I like to tinker around with the latest toys even if I don't particularly need it. I have a home lab with two VMWare ESXi systems built on FX-8320's because at the time they were the cheapest way to get to 8 threads - running a lot of VM's but with each VM doing light work.I also run an IT department so I'm always keeping tabs on what might be coming down the pike when I get ready to update desktops. But there is a sharp divide between what I buy for myself at home and what I buy for users at work. At work, most of our users actually would do fine with an i3. But I'm also keeping an eye out for what AMD has on offer in this range.
Notmyusualid - Tuesday, March 7, 2017 - link
@ Jimster480Sorry pal, but that is false, or inaccurate information.
ALL BUT the lowest model of CPUs in the 2011v3 platform are 40 PCIE lanes. Again, only the entry-level chip (6800K),has 28 lanes:
http://www.anandtech.com/show/10337/the-intel-broa...
But I do agree with you, that this is competing against the HEDT line.
Peace.
slickr - Thursday, March 2, 2017 - link
I'm sorry, but that sound just like Intel PR. I don't usually call people shills, but your reply seems to be straight out of Intel's PR book! First of all more and more games are taking advantage of more cores, you can easily see this especially with DX12 titles where if you have even 16 cores it will take advantage of.So having 8 cores for $330 to $500 is incredible value! We also see that the Ryzen chips are all competitive compared to the $1100 6900k which is where the comparison should be. Performance on 8 cores.
And as I've found out real world performance on 8 cores compared to 4 cores is like night and day. Have you tried running a demanding game, streaming in through OBS to Twitch, with the browser open to read Twitch chat and check other stuff in the process, while also having musicbee open and playing your songs and a separate program to read Twitch donations and text, etc...
This is where 4 core struggles a lot, while 8 core responsiveness is perfect. I can't use my PC if I decide to reduce a video size to a smaller one with a 4 core. Even 8 cores are fully taken advantage off, but through one core you can always do other stuff like watch movie or surf the internet without it struggling to process.
But even if games are your holy grail and what you base your opinion on, then Ryzen does really well. Its equal or slightly slower than the much much more optimized Intel processors. But you have to keep in mind a lot of the game code is optimized solely for Intel. That is what most gamers use, in fact over 80% is Intel based gamers, but developers will optimize for AMD now that they have a competitor on their hands.
We see this all the time, with game developers optimizing for RX 400 series a lot, even though Nvidia has the large majority of share in the market. So I expect to see anywhere from 10% to 25% more performance in games and programs that are also optimized for AMD hardware.
lmcd - Thursday, March 2, 2017 - link
How can you call someone a shill and post this without any self-awareness? Your real-world task is GPU-constrained anyway, since you should be using a GPU capable of both video encode and rendering simultaneously. If not, you can consider excellent features like Intel's Quick Sync, which works even with a primary GPU in use these days.Meteor2 - Friday, March 3, 2017 - link
Game code is optimised for x86.