AMD Zen 2 Microarchitecture Analysis: Ryzen 3000 and EPYC Rome
by Dr. Ian Cutress on June 10, 2019 7:22 PM EST- Posted in
- CPUs
- AMD
- Ryzen
- EPYC
- Infinity Fabric
- PCIe 4.0
- Zen 2
- Rome
- Ryzen 3000
- Ryzen 3rd Gen
Integer Units, Load and Store
The integer unit schedulers can accept up to six micro-ops per cycle, which feed into the 224-entry reorder buffer (up from 192). The Integer unit technically has seven execution ports, comprised of four ALUs (arithmetic logic units) and three AGUs (address generation units).
The schedulers comprise of four 16-entry ALU queues and one 28-entry AGU queue, although the AGU unit can feed 3 micro-ops per cycle into the register file. The AGU queue has increased in size based on AMD’s simulations of instruction distributions in common software. These queues feed into the 180-entry general purpose register file (up from 168), but also keep track of specific ALU operations to prevent potential halting operations.
The three AGUs feed into the load/store unit that can support two 256-bit reads and one 256-bit write per cycle. Not all the three AGUs are equal, judging by the diagram above: AGU2 can only manage stores, whereas AGU0 and AGU1 can do both loads and stores.
The store queue has increased from 44 to 48 entries, and the TLBs for the data cache have also increased. The key metric here though is the load/store bandwidth, as the core can now support 32 bytes per clock, up from 16.
Facebook
Twitter
RSS
216 Comments
View All Comments
Gastec - Wednesday, June 19, 2019 - link
I'm 95% convinced that your micro-stuttering is caused by the GPU/drivers. Disable SLI or Crossfire if that's what you have (you never said what video card you use). And please stop trolling.wurizen - Thursday, June 20, 2019 - link
Really? After all that I said about this... you think that you're 95% sure it's caused by GPU drivers and you want me to disable SLI or Crossfire? Really?Qasar - Thursday, June 20, 2019 - link
have you even mentioned which vid card you are using, or what version the drivers are, or if they are up to date ??Gastec - Wednesday, June 19, 2019 - link
It could also be related to G-sync/FreeSync and your monitor. When debugging the best way is to reduce everything to a minimum.wurizen - Thursday, June 20, 2019 - link
Really, dude? You think it's related to Gsyng and Freesync?Qasar - Thursday, June 20, 2019 - link
it very well could be.. a little while ago.. there was a whole issue with micro stuttering and the fix.. was in new drivers after a certain revision...wurizen - Thursday, June 20, 2019 - link
This is gonna be my last comment regarding my comment about Infinity Fabric High memory latency issue... an objective response would be "It could;" or, "it's quit possible;" or, "110 nanoseconds latency via cross-ccx-memory-performance is nothing to sneeze at or disregard or a non-issue;"instead, i get the replies above; which doesn't need to be repeated since one can just read them. but, just in case, the replies basically say I am trolling such as the most recent from user Gastec; and someone prior I jumped to my conclusion of pointing my scrawny little finger at Infinity Fabric high memory latency; someone plain said I didn't know what I was talking about; etc!
So, I just wanna say that as my one last piece. It's odd no one has aired to the caution of objectivity and just plain responded with "It's possible..."
Instead, we get the usual techligious/fanboyish responses.
Qasar - Thursday, June 20, 2019 - link
it doesnt help, you also havent cited any links or other proof of this other then your own posts... and i quote " And, there are people having head-scratching issues similar to me with Ryzen CPU. " oh.. and where are these other people ?? where are the links and URLs that show this ??? lastly.. IF you have a spare hdd ( ssd or mechanical ) that isnt in use that you could install windows on to, so you wont have to touch the current one you are using, try installing windows on to that, update windows as much as you can via windows update, update all drivers, and do the same things you are doing to get this issue.. and see if you still get it.. if you do.. then it isnt your current install of windows, and it is something else.Carmen00 - Friday, June 21, 2019 - link
Qasar, Gastec et al, I appreciate that you're trying to educate wurizen but when you get responses like "bruh!" and "Really?", I think it's time to call it quits. Like HStewart, feeding wurizen will just encourage him and that makes it difficult to go through the comments and see the important ones. Trust that the majority of Anandtech's readership is indeed savvy enough to know pseudo-technical BS when we encounter it!Qasar - Friday, June 21, 2019 - link
well.. the fact that he didnt cite any one else with this problem, or links to forums/web pages.. kind of showed he was just trolling.. but i figured... was worth a shot to give him some sort of help....