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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Meteor2 - Friday, March 3, 2017 - link
...In which case you'd be better off with a 7700K, looking at the benchmark results. Cheaper too.ddriver - Thursday, March 2, 2017 - link
Ryzen offers the same performance at half the cost. More pci-e lanes is good for io, however quad channel memory is pretty much pointless, aside of pointless synthetic benches. Ryzen might not make it to my personal workstation due to the low pci-e lane count, but it has enough to replace my aging 3770k farm nodes, to which it will be a significant upgrade, provided the chip and platform turn out to be stable and bug free,Intel has gotten lazy and sloppy, bricking products, chipset bugs, they haven't really done anything new architecture wise for years, milking the same old cow.
It is rather silly to assume that gaming dictates CPU prices, this IS NOT a gaming product, if your ass-logic is to be followed, the intel needs to drop the 7700k price to 168, because in games it is barely any faster than the i3-7350K, and has the same pathetic, even lower than ryzen, number of pci-e lanes.
This is a chip for HPC, which gaming is NOT. Go back to the kiddie garden, eight core chips are for grown ups ;)
imaheadcase - Thursday, March 2, 2017 - link
People compare it to gaming, because its the main driving for these type of CPUs, its not even gaming specfic but VR, Graphics modeling, etc. You honestly think people are buying these for offices or industry for complex math problems? lolddriver - Thursday, March 2, 2017 - link
It is not "people" but "fanboys", and they cling to gaming because it is the only workload where intel can offer better performance for the price, albeit by comparing products from different tiers, which is quite frankly moronic.Cars are faster than trucks, so who in the world needs to spend money on trucks? That's the kind of retarded logic you are advocating...
Smart people buy whatever suits their needs. Obviously, if all you do is play games you wouldn't be buying ryzen or a lga2011 system. Just get an unlocked i5 and overclock it, best bang for the buck. You must realize that even if you don't, other people use computers for tasks other than gaming. And for a large portion of them ryzen will be the best deal, because it is versatile - it is good enough for gaming too, while still offering significant performance advantage compare to an intel quad in tasks that are time staking, and are very much competitive with intel's 8 and 10 core chips while delivering more than twice the value, which is important for everyone who doesn't have money to throw away.
Claiming that "gaming is the main driving for these type of CPUs" is foolish to say the least, because games don't benefit from that particular type of CPUs. Most of the games can't even property utilize 4 threads. And this is not likely to change soon, because the overhead of complexity and thread synchronization is not worth it for non-performance demanding tasks such as games.
Lord-Bryan - Thursday, March 2, 2017 - link
That's one really well thought out argumentrarson - Thursday, March 2, 2017 - link
Ryzen's versatility and price are the two biggest factors that make it so good. It might not beat the very best gaming CPU that Intel has, or the very best multi-threaded monster that Intel has in every scenario, but it's competitive with both at half the price of the high-end stuff. Hence, while I do game some and want to build a computer to use for gaming, I also do other stuff like audio production that benefits greatly from Ryzen's multi-threaded performance. To me, it's a no-brainer: Ryzen right now is the best bang-for-the-buck chip for someone who wants all-around high-end performance, by far. Maybe not the 1800X, I kind of think the 1700X is a better value, but still, for most people who want multiple-use performance instead of absolute maximum gaming performance, Ryzen is the clear choice.Ryzen's max clock speeds seem, like Intel's, to be hindered by the total number of cores on chip, so it should be extremely interesting to see how the 4- and 6-core chips overclock once they arrive, and what kind of performance they'll achieve. I actually think that, like Intel, a 4-core Ryzen might be a better gaming chip than the 8-core, and if that's the case, then it might be really darn close to Intel's best Kaby Lake, because like you pointed out, most games aren't threaded well at all.
Additionally, from a gaming perspective, it seems like AMD has done more to push technology forward in that respect than anyone else. They've worked on Mantle, Vulkan, FreeSync, TrueAudio, and others. They've always tried to give performance value by offering more cores, but software has been slow to take advantage of them. Intel is content to stagnate by offering extremely incremental increases because performance is "good enough" so developers have no reason to really try to take advantage of extra cores aside from outside use cases. With Ryzen, AMD is pushing chips towards higher core counts (much like they did with the Athlon X2) but this time, they're trying harder to get developers on board and help them achieve good results. So while it always takes forever for software to better utilize the hardware, once the hardware becomes more common the software will start to follow and you'll see the actual gaming performance improve. Is that a valid reason to buy Ryzen today if your sole focus is gaming? Of course not, but it does bode well for Ryzen owners in the future. The performance can only get better. Can the same be said about Intel? Well, probably not if you're using one of the 4-core chips. It's pretty much a known quantity.
I had high hopes for Bulldozer and Ryzen is the exact opposite of what Bulldozer was. I feel like the CPU market has been stagnant for years and now suddenly there's a reason to be excited. This makes AMD competitive again, which will be good for pricing even if you're an Intel fan. It's been a long wait, but it was worth it, this is a good product.
Notmyusualid - Friday, March 3, 2017 - link
http://www.gamersnexus.net/hwreviews/2822-amd-ryze...Makaveli - Thursday, March 2, 2017 - link
+1 ddriver you destroyed that kid with your logic well done.khanikun - Friday, March 3, 2017 - link
Gaming definitely isn't the main driving force for CPUs, as use case changes. I bought a 7700K for my gaming rig. I'd get a 1700 for a VM host, as I'd like to start building a lab again. It won't be this round though. I'd rather wait for AMD to iron our any kinks and buy the next generation. It's something the 7700K could do, but more cores would definitely make it a much better lab.Meteor2 - Friday, March 3, 2017 - link
Nobody buys mid/high-end consumer chips for HPC. They buy them for gaming. A few for video production. That's it.