mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Hardware

Reply
 
Thread Tools
Old 2020-10-28, 16:59   #1
M344587487
 
M344587487's Avatar
 
"Composite as Heck"
Oct 2017

3·5·72 Posts
Default RDNA2 / Big Navi

AMD announcement: https://www.youtube.com/watch?v=oHpgu-cTjyM


https://www.youtube.com/watch?v=haAPtu06eYI



tl;dr:
  • Infinity cache - "Graphics optimised, high density, high speed cache, based on the Zen L3 cache". graph shows 2.17x bandwidth of infinity cache + 256 bit GDDR6 compared to 384 bit GDDR6 on typical gaming workloads
  • Smart access memory - Zen3 processors can have full access to GPU memory? Showing single digit % performance increase in some games not specifically optimised for it, promises that workloads can specifically optimise for even better performance. Performance figures shown are with this feature enabled so this is one way they've fudged the numbers
6800
  • 60 CU's
  • 1815 MHz game clock
  • 2105 MHz boost clock
  • 128MB infinity cache
  • 16GB GDDR6, 256 bit?
  • 250W TBP
  • November 18th
  • $579
6800XT
  • 72 CU's
  • 2015 MHz game clock
  • 2250 MHz boost clock
  • 128MB infinity cache
  • 16GB GDDR6 256 bit
  • 300W TBP
  • November 18th
  • $649
  • Shown rivalling 3080 in games
6900XT
  • 80 CU's
  • 2015 MHz game clock
  • 2250 MHz boost clock
  • 128MB infinity cache
  • 16GB GDDR6 256 bit?
  • 300W TBP
  • December 8th
  • $999
  • Shown rivalling 3090 in games
At a glance it looks promising. Infinity cache has a chance of being insanely good for our purposes but who knows. The high price is also a good sign that they're confident that they're competitive, in gaming. Timely compute and Linux support, unlikely.

Last fiddled with by M344587487 on 2020-10-28 at 17:14 Reason: GN
M344587487 is offline   Reply With Quote
Old 2020-10-28, 18:05   #2
firejuggler
 
firejuggler's Avatar
 
Apr 2010
Over the rainbow

22·17·37 Posts
Default

The 6800 look like a fair competition to the RTX3070 price wise. Now we need more numbers... like FP 64 performance. For our "need".


edit: ok I found it :

Code:
 FP64 (double) performance                     1,010 GFLOPS (1:16)
Around 3 time the performance or a rtx 3070 (in FP64)
https://www.techpowerup.com/gpu-spec...-rx-6800.c3713

Last fiddled with by firejuggler on 2020-10-28 at 18:25
firejuggler is offline   Reply With Quote
Old 2020-10-28, 21:20   #3
Mark Rose
 
Mark Rose's Avatar
 
"/X\(‘-‘)/X\"
Jan 2013

24·3·61 Posts
Default

Still nowhere near the 3.5 TFL64OPS of the Radeon VII, sadly.

I do wonder how the Navi 10 mining GPU that showed up in recent kernel patches will do. It's Navi 10 though, so probably the same 1/16 FP64 performance.
Mark Rose is offline   Reply With Quote
Old 2020-10-28, 22:22   #4
mackerel
 
mackerel's Avatar
 
Feb 2016
UK

3×7×19 Posts
Default

The cache is the biggest "new" variable I guess. Be really interesting to see how that works out in non-gaming uses.

I think the 6800 will be positioned above 3070, if you compare their relative performance compared to the 3080 and 6800XT respectively.
mackerel is offline   Reply With Quote
Old 2020-10-28, 23:18   #5
moebius
 
moebius's Avatar
 
Jul 2009
Germany

547 Posts
Default

Quote:
Originally Posted by Mark Rose View Post
Still nowhere near the 3.5 TFL64OPS of the Radeon VII, sadly.
Even a Vega 64 still has 0.792 Tflops at FP64. Maybe the fast HBM2 memory is missing.

Last fiddled with by moebius on 2020-10-28 at 23:18
moebius is offline   Reply With Quote
Old 2020-10-29, 00:37   #6
M344587487
 
M344587487's Avatar
 
"Composite as Heck"
Oct 2017

13378 Posts
Default

Quote:
Originally Posted by Mark Rose View Post
Still nowhere near the 3.5 TFL64OPS of the Radeon VII, sadly.
Unfortunately that was never on the cards, Navi has always been about optimising for graphics performance over all else. Good DP is now the realm of CDNA2 and there's a 99% chance that CDNA2 is not the price-performance we're looking for.

Quote:
Originally Posted by Mark Rose View Post
I do wonder how the Navi 10 mining GPU that showed up in recent kernel patches will do. It's Navi 10 though, so probably the same 1/16 FP64 performance.
Wild guess, it's the exact same as an existing card just with all the extraneous features removed and maybe a bios tuned for efficiency. It could just be a ploy to redefine and push Navi 1 as a mining generation. Navi 2 seems to be of less interest to miners as Ethereum and Monero both require random access to a 2GB file so the infinity cache is scuppered, and the raw bandwidth of Navi 2 is not much higher than Navi 1. It's been a while but last I paid attention these two (and derivatives thereof being pedantic) accounted for the vast majority of GPU mining.
M344587487 is offline   Reply With Quote
Old 2020-10-29, 01:43   #7
preda
 
preda's Avatar
 
"Mihai Preda"
Apr 2015

53616 Posts
Default

Quote:
Originally Posted by M344587487 View Post
Timely compute and Linux support, unlikely.
Yep, unfortunately: the hardware is done, time to start work on the software side..
(and by that I don't mean *our* software side, I mean AMD's software side)
preda is offline   Reply With Quote
Old 2020-10-29, 02:05   #8
axn
 
axn's Avatar
 
Jun 2003

113528 Posts
Default

Quote:
Originally Posted by Mark Rose View Post
Still nowhere near the 3.5 TFL64OPS of the Radeon VII, sadly.
This might matter less than you think, to wit...

Quote:
Originally Posted by mackerel View Post
The cache is the biggest "new" variable I guess. Be really interesting to see how that works out in non-gaming uses.
The 128MB cache is big enough to fit our current FFTs in their entirety. This could indeed be very interesting.
axn is online now   Reply With Quote
Old 2020-10-29, 12:43   #9
tServo
 
tServo's Avatar
 
"Marv"
May 2009
near the Tannhäuser Gate

11078 Posts
Default

Quote:
Originally Posted by axn View Post
This might matter less than you think, to wit...



The 128MB cache is big enough to fit our current FFTs in their entirety. This could indeed be very interesting.
It probably depends on whether that cache is able to be manipulated and configured directly by the programmer or if management of it is left to some inflexible on chip algorithm.
tServo is offline   Reply With Quote
Old 2020-11-09, 15:47   #10
Mark Rose
 
Mark Rose's Avatar
 
"/X\(‘-‘)/X\"
Jan 2013

24×3×61 Posts
Default

AMD Radeon RX 6800 1.5x faster than GeForce RTX 3090 in mining

If true, it's going to be fun finding one. I don't think it will have higher FP32 performance than the RTX 3xxx, but this bodes well for INT performance. Could be TF monster.
Mark Rose is offline   Reply With Quote
Old 2020-11-11, 19:23   #11
Mark Rose
 
Mark Rose's Avatar
 
"/X\(‘-‘)/X\"
Jan 2013

24×3×61 Posts
Default

So the above rumour was a bust, but now there are some benchmarks: https://videocardz.com/newz/amd-rade...chmarks-leaked

Last fiddled with by Mark Rose on 2020-11-11 at 19:23
Mark Rose is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Navi (RX 5700, RX 5700XT) M344587487 GPU Computing 29 2019-11-28 14:00

All times are UTC. The time now is 13:48.

Mon Jan 18 13:48:59 UTC 2021 up 46 days, 10 hrs, 0 users, load averages: 2.46, 2.49, 2.58

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.