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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BurntMyBacon - Friday, March 3, 2017 - link
@Gothmoth: "gamer... as if the world is only full with idiotic people who waste their lives playing shooter or RPG´s."PC Gaming happens to be one of the few growing areas in the PC market. Not everyone games, but for those that do, the 7700K is still worth considering. Dropping $500 on the 1800X may not be the best call for those that don't take advantage of the parallelism. Of course, the 1800X wasn't really meant for people who can't take advantage of the parallelism. AMD will have lower cost narrower processors to address that gap. I'm curious as to how the performance/price equation will stand once AMD releases their upper end 6c/12t and 4c/8t processors.
Beany2013 - Friday, March 3, 2017 - link
Sod the 1800X - I need a new VM server, and if I want all the threads (sixteen), I can either drop £450 on a Xeon E5 2620 at 2.1-3ghz (cheapest Intel 16 thread option I can find), or I can spend £100 less, and get a Ryzen 7 1700 (3.0-3.7ghz) and put that extra money towards more RAM so I can run more VMs and get more work done.For those of us who aren't high end gamers - which is basically almost everyone, and a far more significant market - these chips may well give Intel a bloody nose in the workstation space; AMD have confirmed they'll use ECC RAM quite happily.
Photographers, videographers, CAD-CAM, developers etc are a bigger market in terms of raw units than high end gamers, and these chips look like being a pretty compelling option as it stands.
Steven R
Beany2013 - Friday, March 3, 2017 - link
(VM server for home, I should have noted - for work, I'll see how the Ryzen based opterons and supermicro mobos etc pan out - money is important in these factors, but I'm not a moron, and I'm not going to run production gear on gaming hardware, natch....)BurntMyBacon - Friday, March 3, 2017 - link
@Beany2013: "I need a new VM server, and if I want all the threads (sixteen), I can either drop £450 on a Xeon E5 2620 at 2.1-3ghz (cheapest Intel 16 thread option I can find), or I can spend £100 less, and get a Ryzen 7 1700 (3.0-3.7ghz) and put that extra money towards more RAM so I can run more VMs and get more work done."It is clear by this statement that you fall into the category of people that can take advantage of the parallelism. Therefore, my statement doesn't apply to your presented in the slightest.
I don't disagree that the Ryzen 7 series has a lot to offer to a lot of people (myself included). If I were in the market today, I'd be looking long and hard at an R7 1700X. The minor drop in gaming performance is less significant to me than the increase in performance for many other tasks I use my computer for. I do a little bit of dabbling in a lot of different things (most of which benefit from high thread count). I have noticed that for the set of applications I have open simultaneously and the tasks I have running, my computer is more responsive with more cores or threads, but single threaded performance is still important to the individual tasks.
In my workflow: (i3 < i5/FX-8xxx < i7 <? R7)
My point was that there is in fact a not so insignificant market of people putting computers together for the primary purpose of gaming. This market appears, by all metrics, to be growing. For this market, Intel's i7-7700K or better yet i5-7600K are still viable options that provide better performance/price than AMD's current options. I'll repeat: "AMD will have lower cost narrower processors to address that gap. I'm curious as to how the performance/price equation will stand once AMD releases their upper end 6c/12t and 4c/8t processors."
Cooe - Sunday, February 28, 2021 - link
"or better yet i5-7600K"Arguably the most short-sited statement in this entire comments section lol. The 4c/4t i5's had roughly equal gaming performance to Ryzen at launch but with ZERO headroom left for the future. This is why the i5-7600K gets absolutely freaking ROFLSTOMPED by the R5 1600 in modern titles/game engines.
JMB1897 - Friday, March 3, 2017 - link
Compelling, but I don't think it's totally there yet. I'd be worried about the memory issues. Increased latency as you add more DIMMs and dual vs quad channel. I'd spend that extra 100 on a Xeon personally.Sttm - Friday, March 3, 2017 - link
Thats who buys off the shelf CPUs thats cost $$$, Gamers. Thats who AMD needs to please with their product. GAMERS. Thats why AMD's stock has been tanking since Ryzen reviews went up, because GAMERS are the demographic that matters when it comes to performance CPU sales.deltaFx2 - Saturday, March 4, 2017 - link
@Sttm: You have an inflated opinion of the impact of gamers. No, AMD's stock isn't tanking because of gamers. I suggest you also look at Nvidia's stock, which is well down from its high of ~120, to ~98. Wed-Friday, Nvidia dropped from 105 to 98, and it dipped below that to ~96 at one point. That's roughly 7-8%. The two stocks are often correlated on drops, with AMD amplifying nvidia's drop. Both do GPUs, see? Some people make tonnes of money shorting AMD (and in recent times have lost their shirt doing so).Here's the truth: All Desktop, as per Lisa Su, is a 5 bn TAM market and gaming is part of this (let's say 50%). Nothing to scoff at, sure, but compared to laptop and server, it's a rounding error. There's NOTHING in these tests/reviews to suggest that AMD will suck in those markets; in fact, quite the opposite: power looks good, perf looks good. AMD's stock (long term) won't tank on the whims of gamers. They help get the mindshare, which is the only reason they're worth catering to (they tend to be a vocal, passionate, and sometimes irrational lot. You won't see datacenter gurus doing the stuff that gamers do. They certainly won't shoot each other over whose GPU is the best).
cmdrdredd - Saturday, March 4, 2017 - link
Believe it or not there are millions of people worldwide who pretty much use their PC for two things. The internet (web browsing, email etc) and gaming. You don't need 16 threads to check email and read forums either so gaming performance is going to be critical. It's not just the CPU performance, it's the entire platform that contributes to Gaming related performance.sans - Thursday, March 2, 2017 - link
Yeah, stick with Intel because Intel is the standard and its products are the best for each respective market. AMD is a total failure.