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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HighTech4US - Friday, March 3, 2017 - link
Why?The 1800X loses to the 7700K why would you think the 1500X would outperform the 1800X?
EasyListening - Friday, March 3, 2017 - link
haha /facepalm. Because, padawan, with less cores, you can clock the cores higher, increasing single threaded performance. 1500X/1600X might be the sweet spot for Ryzen gaming. Time will tell.Meteor2 - Friday, March 3, 2017 - link
Do you know of any manufacturer which actually does that? Clocks CPUs with lower core counts higher? I don't.phexac - Friday, March 3, 2017 - link
"Do you know of any manufacturer which actually does that? Clocks CPUs with lower core counts higher? I don't."You mean besides Intel? Where their 4-core chips are clocked higher than 6-core, which is clocked higher than 8-core, which is clocked higher than 10-core?
Like seriously, you can't think of a CPU manufacturer that does this?
Meteor2 - Saturday, March 4, 2017 - link
Top i7 is the 7700K with a turbo max of 4.5 GHz. Top i5 is the 7600K with a turbo max of 4.2 GHz.The Xeon E5 v4s max out at 3.6 GHz regardless of core count.
Intel's i7s and higher core-count Xeons also have larger caches.
Notmyusualid - Tuesday, March 7, 2017 - link
@Meteor2:Except for the single-socket Xeons aka 'uni-processor' chips, which I'm reliably told are multiplier-unlocked. There are a few 8-core E5-1660 & E5-1680 chips out there at nearly 5GHz, if you can stomach the unbelievable price. And I've NEVER seen on on Flea-bay cheap either, or I'd have grabbed it immediately.
http://ark.intel.com/products/92992
Ananke - Friday, March 3, 2017 - link
Because, the 1500X will be 4.0GHz + part, and very likely performance will be higher than 7700k for less than half price. Ryzen architecture is similar to Intel's sandy bridge, i.e. performance per cycle is same, so for gaming higher clocked processors will be better. 1500X will be probably the best choice for gaming.Meteor2 - Friday, March 3, 2017 - link
It's not. The 1500X boosts to 3.8 GHz.https://www.google.co.uk/amp/wccftech.com/amd-ryze...
Meteor2 - Friday, March 3, 2017 - link
Bit disappointed. In terms of performance against power consumption, Intel still wins. Probably because of their process lead.Zen keeps AMD in the game though, and I think we might see parity when GF reaches (a real) 7 nm in a couple of years.
MongGrel - Thursday, March 9, 2017 - link
If you even imply that in the forums here you will get smacked to the curb, and eve get slapped to the curb more if you ask for a explanation why you were smacked to the curb.