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AMD Zen 2 (Refresh) 3900XT/3800XT/3600XT

Discussion in 'CPUs' started by The Old School Gamer, May 23, 2020.

  1. Grim5

    Mobster

    Joined: Feb 6, 2019

    Posts: 3,598

    Correct, I know what video you're talking about and IIRC the scaling shown there suggests that if Ryzen 3000 wants to beat Intel just with higher clock speeds it would need about 7ghz to do so - the conclusion is that gaming performance doesn't scale well on ryzen 3000 with higher clocks, there are other bottlenecks in the architecture that are too great, such as the memory latency
     
  2. SupraWez

    Wise Guy

    Joined: Nov 17, 2007

    Posts: 2,273

    That would explain why single CCX models appear to be better for gaming.

    Where else is the latency, the CCX to IO, I guess the affinity fabric.

    I wonder then, on one of these new XT models disable CCX so only one is active and ramp the IF up keeping the ratio to 1:2 with memory, would be interesting as a test to see what difference it makes, obviously completely pointless for 90% of tasks where performance is way more than needed :D
     
  3. MrPils

    Gangster

    Joined: Jun 29, 2009

    Posts: 222

    Tell you tomorrow, my 3900XT shipped this morning :)
     
  4. CAT-THE-FIFTH

    Capodecina

    Joined: Nov 9, 2009

    Posts: 19,727

    Location: Planet Earth

    It's OK - I vented a lot about their B450/Zen3 moves,but ATM I think AMD is more deserving of my money than Intel. However,as I said if both companies start trying to take the mickey,I will just upgrade less often. I think the important thing is to wait until the price/performance is in your own personal ballpark,if you can hold off upgrading. Too many of these companies rely on people not having any self control,so try and exploit this.

    I was saying this for years,as you could see Zen based CPUs underperforming in latency sensitive games. So when they fixed other sources of latency,ie,the caches,certain games improved a decent amount. The three main forms of latency Zen3 will need to tackle are memory-CCX latency,chiplet to chiplet latency,and inter-CCX latency.

    The 8 core SKUs have a single chiplet so lack the chiplet to chiplet latency. However the huge L3 cache probably makes up for some aspects of the latency.

    But when the Zen2 based APUs are released,they will be one SOC with reduced memory-CCX latency and no chiplet to chiplet latency. It will be interesting to see how these perform even with the lower amount of L3 cache.
     
    Last edited: Jul 8, 2020
  5. Jamin280672

    Wise Guy

    Joined: Feb 12, 2014

    Posts: 1,909

    Location: Halesowen West Mids

    I'll tell you later, my 3800xt is arriving today, and fabric needs to be run 1:1, 2:1 is punishing on latency, but I already know my ram will do 4000mhz, so if the infinity fabric does 2000mhz then I should be laughing.
     
  6. SupraWez

    Wise Guy

    Joined: Nov 17, 2007

    Posts: 2,273

    Thanks, looking forward to this testing :D
     
  7. jigger

    Capodecina

    Joined: May 28, 2007

    Posts: 12,630

    That would be a substantial drop in upgrade to my desktop system.
     
  8. Boot_Loop

    Gangster

    Joined: Jul 12, 2016

    Posts: 261

    Yeah but what about epeen?

    Seriously though, adding 100-200mhz on top of single core boost is enough for Intel to call Comet Lake a whole new gen and that makes negligible perf difference so here we are. Some people like the numbers. Seeing 4599Mhz on CPU-Z with one of these would make me twitch a little down the nether region if nothing else.
     
  9. Jamin280672

    Wise Guy

    Joined: Feb 12, 2014

    Posts: 1,909

    Location: Halesowen West Mids

    I plan to manually overclock it, id love it if it did 4.6ghz across all cores and 2000mhz IF, I did have a 3900X, but to be honest I wasnt utilizing it so I sold it, it was a rubbish chip anyway, I was going to buy the 3800X and thought may as well just wait for the 3800XT.
     
  10. Richdog

    Capodecina

    Joined: Sep 8, 2005

    Posts: 24,619

    Location: Utopia

    Sure, if that's your thing. *shrugs* :D
     
  11. SupraWez

    Wise Guy

    Joined: Nov 17, 2007

    Posts: 2,273

    I am looking to drop in a replacement for my 1700 which is manually overclocked to 3.8-3.9 ish, so looking at IPC improvements and 600-700 Mhz jump :D

    YES PLEASE :D
     
  12. Jamin280672

    Wise Guy

    Joined: Feb 12, 2014

    Posts: 1,909

    Location: Halesowen West Mids

    Well its in, went straight to 4.6ghz, tweaked the bios here and there, enabled XMP for my RAM, passed both Cinebench easily so ran 50 passes of IBT AVX, which it passed, 1.35v set in the bios, under load its drooping to 1.33v, any lower and it crashes to a black screen then reboot, going to play with the fabric now.

    Seems very snappy, my boot is quicker than with my 3900X, but then that does only boost to 4.6ghz when it feels like it and only for short bursts.
     
  13. SupraWez

    Wise Guy

    Joined: Nov 17, 2007

    Posts: 2,273

    Very interesting indeed :D
     
  14. hyperseven

    Soldato

    Joined: May 1, 2013

    Posts: 7,095

    Location: M28

    So the 3600XT is the best of the bunch of these respins over their X counterparts.

    Ah well, will hold off until Zen3.

     
  15. jigger

    Capodecina

    Joined: May 28, 2007

    Posts: 12,630

    Seems like the 3800XT.
     
  16. Boot_Loop

    Gangster

    Joined: Jul 12, 2016

    Posts: 261

    I might put that on just before bed tonight to send me off. Lol he's alright and content is interesting but very monotonous.

    I think it depends on the sample these reviewers get, Aussies HU seemed to get a crap 3600XT by comparison.
     
  17. Grim5

    Mobster

    Joined: Feb 6, 2019

    Posts: 3,598

    IF/FCLK overclocking yet? Try for 2000mhz
     
  18. Joxeon

    Wise Guy

    Joined: Oct 15, 2019

    Posts: 2,022

    Location: Uk

    Thats the smart option as the 4000 series will likely wipe the floor with the refreshes when they're released in a couple of months.
     
  19. Jamin280672

    Wise Guy

    Joined: Feb 12, 2014

    Posts: 1,909

    Location: Halesowen West Mids

    Testing still, 4.6ghz, IF wouldnt go any further than 1900mhz, but ram is at 3800mhz 16-18-16-36-GDM 1.41v, will post some benchmarks soon, just making sure its stable, its quick thats for sure, said in an earlier post, I was going to buy a 3800X anyway so thought I may as well try the XT version instead.

    I'll still buy a Ryzen 4000, will probably just give this one to my Dad.

    I'll edit this post with benchmarks as I go along, that will do for memtest: https://imgur.com/0BlWqD1

    CPU-Z Benchmark very interesting validation: https://valid.x86.fr/lv8c7h

    Cinebench R20 Single & Multi: https://imgur.com/OQYDnPo

    Bear in mind im still tweaking the ram a little.

    Dram Calc default test: https://imgur.com/HSOTjEl
     
    Last edited: Jul 9, 2020
  20. Pannalicour

    Gangster

    Joined: May 5, 2017

    Posts: 113

    This latency in games is ********. At his point its all about how a game is optimised. Look at far cry 5: 30 fps more on intel side in comparison with amd. Thats rediculious. These games are horrible written. Look at other games where amd is doing great. The better question is, how come one game is more latency sensitive than the other?

    Btw I didn't do research on this one. Isn't so that zen+ has better latency than zen 2? How come zen 2 is performing better than?

    I really think its comes down to how wel the game engine is written.