Zen 3 speculation

[axn]

Originally Posted by Xyzzy

Is it a sure thing that the 5600X has six cores on one chiplet instead of three cores each on two chiplets?

Yes. The base unit for Zen 3 is 8 cores + 32 MB L3 compared to 4 cores + 16 MB L3 of Zen 2.

EDIT:- Do you have a 500 series motherboard, BTW?

[Xyzzy]

Originally Posted by axn

EDIT:- Do you have a 500 series motherboard, BTW?

We plan to get this: https://rog.asus.com/articles/crossh...iii-dark-hero/

[M344587487]

It is a sure thing that the 5600X has 6 cores on 1 CCX, 6+0. If they did a 3+3 config they would give it a different name like they did with the 3100 and 3300, but they won't do a 3+3 config on Zen 3 as that would require two incredibly poor quality dies. I'm predicting the lowest part will be 4+0 which might be OEM-only and only come much later when enough very low quality dies have been salvaged.



Some retailers have implemented captcha at different points in the process so at least login and add the CPU to the basket if you can. Find out exactly when it's meant to go live and periodically refresh. It's hard to predict how long before it goes out of stock but you can safely bet that it will.

[mackerel]

Anandtech have some details on the architecture changes relative to Zen 2. FP multiplies don't seem to have any extra units, but what were formerly shown as MUL blocks are now MUL/MAC blocks, with the two ADD blocks still present separately. Does that mean it can do more FADDs?

There's also mention that FMA goes from 5 cycle to 4 cycles. This reminds me of the difference between Haswell and Skylake, which saw the same drop.

Assuming it can be kept fed, which should be helped with the unified L3, there is some potential for FP IPC improvement.

Who's getting one to try?

[M344587487]

The review embargo lifted 1h20 ago. Here are some videos:
GN: https://www.youtube.com/watch?v=72AHENDeTEI
HU: https://www.youtube.com/watch?v=zsfvRw74h30
RR: https://www.youtube.com/watch?v=dQw4w9WgXcQ


Phoronix 5900X/5950X: https://www.phoronix.com/vr.php?view=29687



Judging by these early reviews Zen 3 is looking very promising. Instead of Zen 2 whose advertised stock boosts were rarely hit, Zen 3's advertised stock specs are often exceeded. The 5950X stock also has lower power draw than the previous generation 3950X and 3900X it's replacing, that's under full load with much better performance and using the same node which is impressive. The main channels all seem to be releasing videos on the parts in descending order over the comings hours/days so not too long until we have a more complete picture.

[Xyzzy]

We managed to order a 5600X via AMD's direct site.



Edit: Here is our parts list for this build:

CPU: AMD Ryzen 5 5600X 3.7 GHz 6-Core Processor
Memory: G.Skill Trident Z RGB 32 GB (2 x 16 GB) DDR4-4000 CL16 Memory
Storage: Samsung 980 Pro 1 TB M.2-2280 NVME Solid State Drive
Video Card: NVIDIA GeForce RTX 3080 10 GB Founders Edition Video Card
Case: Fractal Design Define 7 Compact ATX Mid Tower Case
Power Supply: Fractal Design Ion+ 860 W 80+ Platinum Certified Fully Modular ATX Power Supply

[Mark Rose]

Keep in mind a side effect of the L3 being merged is the L3 bandwidth per core has been halved. Not sure what kind of effect that will have, but it could be significant.

[mackerel]

Originally Posted by Mark Rose

Keep in mind a side effect of the L3 being merged is the L3 bandwidth per core has been halved. Not sure what kind of effect that will have, but it could be significant.

Interesting point. It might not necessarily be halved due to various changes in the way Zen 3 works, but I take the point that we have more cores hanging off a single pool.

I tried to look around and see if anyone has tried to measure it. Many sites seem to measure in latency which I'm not sure I can translate into bandwidth. However I did find this: https://www.hardwaretimes.com/amd-ry...ral-deep-dive/
The multi-core effective bandwidth at various data sizes is interesting, and around the L3 size region, the 5600X is lower than 3600X. The chart scaling doesn't help, but let's say it is roughly 300GB/s in the middle of that zone. For indication, single channel 3200 ram is about 25GB/s. Given a single L3 cache only has to feed at most 8 cores, we're still looking at an effective bandwidth per core above that ram scenario.

Assuming bandwidth > latency then I think there is still a good chance this is sufficient for many use cases. I'll let those who are actually getting samples to confirm.

[lalera]

hi,
this is pricey and hopefully good hardware
i would take 2x 8gb ram and a 8core cpu (5800x) or higher

[Xyzzy]

Originally Posted by Xyzzy

We managed to order a 5600X via AMD's direct site.

It will be delivered tomorrow. We are surprised at how fast it shipped and that they are going to deliver it on a Sunday. We don't have a motherboard for it yet, though. Quite a few reviews commented on how power-efficient the 5600X is. Interesting!

https://www.anandtech.com/show/16214...5700x-tested/8

Bonus: https://www.notebookcheck.net/AMD-di....502429.0.html

[Xyzzy]

Originally Posted by lalera

…i would take 2x 8gb ram…

We want dual rank memory.

https://www.mersenneforum.org/showthread.php?t=26071