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
@ShieTar: "Well, the point of low-resolution testing is, that at normal resolutions you will always be GPU-restricted."If this statement is accepted as true, then by deduction, for people playing at normal (or high) resolutions, gaming is not a differentiator and therefore unimportant to the CPU selection process. If gaming is your only criteria for CPU selection, then that means you can get the cheapest CPU possible until you are not GPU restricted.
@ShieTar: "The most interesting question will be how Ryzen performs on those few modern games which manage to be CPU-restricted even in relevant resolutions, e.g. Battlefield 1 Multiplayer."
I agree here fully. Show CPU heavy titles to tease out the difference between CPUs. Artificially low resolutions are academic at best. That said, according to Steam Surveys, just over half of their respondents are playing at resolutions less than 1080P. Over a third are playing at 1366x768 or less. Though, I suspect the overlap between people playing at these resolutions and people using high end processors is pretty small.
Average frame rate is fairly uninteresting in most games for high end CPUs, due to being GPU bound or using unrealistic settings. Some, more interesting, metrics are min frame rate, frame time distribution (or simply graph it), frame time consistency, and similar. These metrics do more to show how different CPUs will change the experience for the player in a configuration the player is more likely to use.
Lord-Bryan - Thursday, March 2, 2017 - link
Who buys a 500 dollar cpu to play games at 720p res. All that talk is just BS.JMB1897 - Friday, March 3, 2017 - link
That test is not done for real world testing reasons. At that low resolution, you're not GPU bound, you're CPU bound. That's why the test exists.Now advance a few years into the future when you still have your $500 Ryzen 7 CPU and a brand new GPU - you may suddenly become CPU bound even at QHD or 4k, whereas a 7700k might not quite be CPU bound just yet.
MAC001010 - Saturday, March 4, 2017 - link
Or a few years in the future (when you get your new GPU) you find that games have become more demanding but better multi-threaded, in which case your Ryzen 7 CPU works fine and the 7700k has become a bottleneck despite its high single-threaded performance.This illustrates the inherent difficulty of comparing high freq. CPUs to high core count CPUs in regards to future potential performance.
cmdrdredd - Saturday, March 4, 2017 - link
"Or a few years in the future (when you get your new GPU) you find that games have become more demanding but better multi-threaded, in which case your Ryzen 7 CPU works fine and the 7700k has become a bottleneck despite its high single-threaded performance."Maybe, the overclocking scenario is also important. Most gamers will overclock to get a bit of a boost. I have yet to replace my 4.5Ghz 3570k even though new CPUs offer more raw performance, the need hasn't been there yet.
One other interesting thing is how Microsoft's PlayReady 3.0 will be supported for 4k HDR video content protection. So far I know Kaby Lake supports it, but haven't heard about any of AMD's offerings unless I missed it somewhere.
Cooe - Sunday, February 28, 2021 - link
Lol, except here in reality the EXACT OPPOSITE thing happened. A 6-core/12-thread Ryzen 5 1600 still holds up GREAT in modern titles/game engines thanks to the massive advantage in extra CPU threads. A 4c/4t i5-7600K otoh? Nowadays it performs absolutely freaking TERRIBLY!!!basha - Thursday, March 2, 2017 - link
all the reviews i read are using NVidia 1080 gfx card. my understanding is AMD graphics has better implementation of DX12 with ability to use multiple cores. I would like to see benchmarks with something like RX480 crosfire with 1700x. this would be in the similar budget as i7 7700 + GTX 1080.Notmyusualid - Friday, March 3, 2017 - link
http://www.gamersnexus.net/hwreviews/2822-amd-ryze...cmdrdredd - Saturday, March 4, 2017 - link
Overclocking will be interesting. I don't use my PC for much besides gaming and lately it hasn't been a lot of that either due to lack of compelling titles. However, I would still be interested in seeing what it can offer here too for whenever I finally break down and decide I need to replace my 3570k @ 4.5Ghz.Midwayman - Thursday, March 2, 2017 - link
Here's hoping the 1600x hits the same gaming benches as the 1800x when OC'd. $500 for the 1800x is fine, Its just not the best value for gaming. Just like the i5's having been better value gaming systems in the past.