AMD: Navi Speculation, Rumours and Discussion [2019-2020]

I don’t believe that’s how performance per watt is calculated. What you’re describing is just increasing CU count and decreasing frequency to obtain more processor power for less wattage.
Performance per watt should be a shift on the whole power curve If I understand it correct. Not moving down the power curve.

 

Never remembered the 50% performance per watt claim, but looking it up, yep there it is all official.

If we go off that, and total power for a 5700xt is 270 watts, well then: 15 teraflops for 270 watts, crank it up to 350 at max, just under 20 teraflops. Now how this does against the 30XX series ideally (IE what's shown so far) would put it over a 3080 but just under a 3090. What the two will do versus less ideal conditions is unknown, how does Navi handle raytracing, is Ampere really this bad in some title or is that just totally not ready drivers, well we can wait to see. But if they hit that 50% here's a few cards we could see. 350 watts max going to lower: 6900xt 24/16bg? ram/19.5 teraflops $1000-$800; 6800xt 21/14gb? ram/16.5 teraflops $600. 6700xt 16gb 12.5 teraflops 16gb ram $500-450; 6700 8/16gb 10 teraflops $400-350. This last, lowest card should rate somewhere about a 2070 super or higher, we'll see.

That's assuming a lot of things as usual. But one high end die with two SKUs and one middle die with 2. Seems reasonable, but as pointed out AMD could've done better:

Would like to point out that the series X is only rated at about 22% faster than a 5700xt. But that powerdraw is significantly lower than what anand has for the 5700xt actual power draw. While we can see that the Series X is downclocked from a 5700xt, 30% more CUs for 20% more ideal performance, it's still a huge gap, Nvidia better hope RDNA2 isn't that efficient.

 

My turn for some napkin math.

There was a picture indicating the Xbox Series X PSU Could deliver up to ~315W, as someone just mentioned above. No console is going to risk using near the max capability of the PSU, so count 250W max for constant usage.
If you take the power the CPU, SSD, other I/O components need to use, 150W is a reasonable estimate for the GPU.
Additionally, assuming AMD complies with their 50% power consumption decrease for the same performance, we can say;

52/40=1.3 (the XSX has 30% more CUs than the 5700XT)
1.3*225W = 293W
50% power consumption is 293*0.5=146W

They are around the same clocks, give or take a few 100 MHz, so, despite knowing that power consumption is not linear, that should still be a viable calculation to give some ballpark figures.
Using the CU ratio of big Navi and XSX (80/52) with its 150W power consumption nets you approximately 230W of usage. Assuming it could reach 2.2GHz, multiply by 2.2/1.8 (PS5 frequency divided by XSX frequency) nets you around 282W. Some lower efficiency is expected due to the higher clocks, so around 300W seems reasonable. It might be 2GHz instead of 2.2 GHz depending on how good RDNA2 can scale with power.
Back calculating the power consumption per CU, gives you a value of 3.75W/CU. If you multiply this by 1.5 (50% increase in power consumption), this nets you the power consumption of the 5700XT. It all balances out. So the 80CU navi should have around 300W of power consumption.

And this card should be at least 5% faster than the RTX 3080.

 

If they decide pushing it just to beat 3080 they better not screw it up with another 290X jet furnace. Ain't no one buying that.

 

O-ha-ha.

Pushing it?
Also the cooling actual should be around Sapphire Pulse grade boards (or a bit higher), assuming AMD didn't make some fucktarded glaring omission which they're bound to.

 

"calculations" are fun

XBX GPU: 130-140w; 52CU; 1825MHz
5700XT GPU: 180w (only the rated TDP for the GPU); 40CU; 1905MHz

52/40 x 180w = 234w, so maybe 220w due to the lower frequency.

220/130= +69% better efficiency
220/140= +57% better efficiency

The +50% seems to be real

BigNavi with 80CU + 2250MHz

80/52 x (2250/1825)² x 130w = 304w (only for the GPU, we will see how much power the RAM will need)

2250 / 1905 x (80/40) = 2,36x 5700XT

2800Ti = ~50% faster than 5700XT
2,36/1,5 = 1,57

so I expect BigNavi to be between 55% and 60% faster than a 2800Ti, without taking into account the IPC improvements of RDNA2. If the power target of AMD is lower (275w?) than the performance would be lower too of course.

 

I think it depends on where you take the 50%. If you are getting 50% better or more than it’s 7.5 + 50% which is 11TF.

If you are going the other way, 50% of 15TF than it becomes 7.5TF. But 7.5 to 15 is a 100% improvement.

so 50% improvement should be to 11TF.

 

Well, yesterday there was a tweet from Frank Azor



So maybe today we will geto some info and a date for the announcement?

 

Yeah.

 

https://www.anandtech.com/show/14618/the-amd-radeon-rx-5700-xt-rx-5700-review/15
5700XT most often runs a bit higher than its game clock on average, right around the 1825MHz mark that the Series X GPU runs at. The difference in frequency is minimal. Increased CU count, that's true, but the Series X seems to show an even greater than 50% perf/watt increase over the 5700XT if I'm not mistaken.

 

Vega CUs satisfied that claim through rapid packed math already. It's marketing after all.

To be fair, the footnote regarding this in their most recent corp. presentation still says it's based on AMD internal estimates. Make of that what you will.

 

Excuse me for asking... you are implying, that you know something about Big Navi and AMDs Plans ... whats your background? thanks!

 

Well uh, they've been timing October launch for some time now.

I buy things in volume.

 

Well glad you finally acknowledged it.

And desktop GPU power consumption is also variable depending on workload. We do have a maximum Wattage as per you so anything below is obviously a plus. Either ways, the discussion was on XSX since it is also RDNA2. The XSX's 52 CU GPU consumes sub ~150W at 1.825 Ghz ( which is similar to Navi 10 desktop clocks). PS5 GPU boosts up to 2.2 Ghz at presumably similar or lower power levels. These are all on the same/similar process nodes. Yet you seem to think there's zero relevance.

Could be a bit higher than 30% even, latest Techpowerup 4K results have the 2080ti at 143% of 5700XT. But doubling CU's wouldn't scale linearly of course (or at all as per some...) so I think the 30% figure sounds about right. If the Azor tweet was about a reveal, we'll know soon!

RDNA2 RT hardware is shared with the TMUs, they wont be functional at the same time. And with minimal extra silicon as stated already. Wouldn't rule it out of course, but it is highly unlikely to consume extra power compared to pure raster performance. Said IHV is probably concerned with its own power measurements.

 

Seen this mostly wrt to TAMs.

 

Someone at marketing team spazzed and thought it was a good idea.
C'mon it's the woodscrews company.

Oh wait they also did a video about fans and cooling like 2 weeks ago.

 

Na, it's more than a lapsus at sending out random packages from NVLogistics. They had separate slides on their techday briefings, a separate NDA on the tools and they sent out the kits to their NDA partners.

 

The RDNA marketing material for perf/w comparison had a very convoluted explanation of what they tested.
https://forum.beyond3d.com/threads/...nd-discussion-2019.61042/page-46#post-2073559
Slides from the above link- AMD Next Horizon: Gaming PDF

AMD's Radeon Image Sharpening (RIS) was better than DLSS 1.0, and there was talk about AMD using RadeonML to update and offer a comparable solution to DLSS 2.0 but haven't heard anything further about it.
I would expect something would be mentioned leading up to launch, whether it is ready at launch or shortly after, I think it is agreed they need something and the consoles point towards that being the case.

 

Can we please keep this thread about AMD? Maybe take the AMD/Nvidia comparisons discussion to the Speculative comparison thread: https://forum.beyond3d.com/threads/speculation-gpu-performance-comparisons-of-2020-spawn.61885/