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 - Sunday, March 5, 2017 - link
If you have a Q6600, I can understand that, but the QX9650 ain't too bad. ;)Marburg U - Monday, March 6, 2017 - link
I'm on a Q9550 running at 3.8 for the past 6 years. I could still run modern games at 1050p, with a r9 270x, but that's the best i can squeeze out of it. Mind that i'm still on DDR2 (my motherboard turns 10 in a few months). I really want to embrace a ultra wide monitor.mapesdhs - Monday, March 6, 2017 - link
Moving up to 2560x1440 may indeed benefit from faster RAM, but it probably depends on the game. Likewise, CPU dependencies vary, and they can lessen at higher resolutions, though this isn't always the case. Still, good point about DDR2 there. To what kind of GPU were you thinking of upgrading? Highend like 1080 Ti? Mid-range? Used GTX 980s are a good deal these days, and a bunch of used 980 Tis will likely hit the market shortly. I've tested 980 SLI with older platforms, actually not too bad, though I've not done tests with my QX9650 yet, started off at the low end to get through the pain. :D (P4/3.4 on an ASUS Striker II Extreme, it's almost embarassing)Ian.
Meditari - Monday, March 6, 2017 - link
I'm actually using a Q9550 that's running at 3.8 as well. I have a 980ti and it can do 4k, albeit at 25-30fps in newer games like Witcher 3. Fairly certain a 1080ti would work great with a Q9550, but I feel like the time for these chips is coming to an end. Still incredible that a 8 year old chip can still hold it's own by just upgrading the GPUmapesdhs - Tuesday, March 7, 2017 - link
Intriguing! Many people don't even try to use such a card on an older mbd, they just assume from sites reviews that it's not worth doing. Can you run 3DMark11/13? What results do you get? You won't be able to cite the URLs here directly, but you can mention the submission numbers and I can compare them to my 980 Ti running on newer CPUs (the first tests I do with every GPU I obtain are with a 5GHz 2700K, at which speed it has the same multithreaded performance as a stock 6700K).What do you get for CB 11.5 and CB R15 single/multi?
What mbd are you using? I ask because some later S775 mbds did use DDR3, albeit not at quite the speeds possible with Z68, etc. In other words, you could move the parts on a better mbd as an intermediate step, though finding such a board could be difficult. Hmm, given the value often placed on such boards, it'd probably be easier to pick up a used 3930K and a board to go with it, that would be fairly low cost.
Or of course just splash for a 1700X. 8)
Ian.
Notmyusualid - Tuesday, March 7, 2017 - link
Welcome to the 21:9 fan club brother.But be careful of the 1920x1080 screens, my brother's 21:9 doesn't look half as good as my 3440x1440 screen.. It just needs that little bit more verticle resoultion.
My pals 4k screen is lovely, and brings his 4GB 980 GTX to its knees. Worse aspect ratio (in my opinion), and too many pixels (for now) to draw.
Careful of second-hand purchases too, many panels with backlight-bleed issues out there, and they are returns for that reason, again, in my opinion.
AnnonymousCoward - Monday, March 6, 2017 - link
Long story short:20% lower single-thread than Intel
70% higher multi-thread due to 8 cores
$330-$500
Mugur - Tuesday, March 7, 2017 - link
Actually, on average -6.8% IPC versus Kaby Lake (at the same frequency) - I believe this came directly from AMD. Add to this a lower grade 14nm process (GF again) that is biting AMD again and again (see last year RX480). Motherboard issues (memory, HPET), OS/application issues (SMT, lack of optimizations).All in all, I'm really impressed of what they achieved with such obstacles.
AnnonymousCoward - Tuesday, March 7, 2017 - link
Just looking at CineBench at a given TDP and price, AMD is 20% lower. That's the high level answer, regardless of IPC * clock frequency. I agree it's a huge win for AMD, and for users who need multicore performance.Cooe - Monday, March 1, 2021 - link
Maybe compare to Intel's Broadwell-E chips with actually similar core counts.... -_-