davis.anthony
Veteran
I'm confused by this comment, can you clarify please as I assume it's directed at me?
AMD RX 7900XTX and RX 7900XT Reviews
- Thread starter DavidGraham
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I'm confused by this comment, can you clarify please as I assume it's directed at me?
DavidGraham
Veteran
At least five in any given GPU, probably.
The speculation is that they separated these clocks domains in response to a bug that is preventing it from reaching clockspeed targets, and then marketed the separate clocks as a performance enhancing feature (which is technically true). It is a baseless but reasonable theory.
Shader core isn't chiplets. Everything else is in one GCD, except for Infinity Cache and memory controllers which live on 6 chiplets (16MB + 64bit mem controller (4x16bit) each)
So potentially it's power balancing and favours the chip with the shader engines and starves the chiplets with the cache and memory interfaces.
Edit: What is jay actually doing in that video when he sets the clock? Is he setting a fixed clock? Is he setting a max clock? When you increase the max does it increase the min, like shifting a range? I haven't had an amd gpu since the 2000s, so I'm way out of the loop as to how their overclocking works.
Edit: Where I'm going with this is, if you're setting a fixed clock or shifting a range, maybe what you're setting is the shader core clock can't drop low enough to sustain power to the chiplets which causes the vram clock to drop. What we've seen in furmark and some games is the shader clock will drop really low to stay within the power budget. Maybe jay has basically disabled it's ability to manage power by reducing the shader clock, so it shifts to secondary power management which is adjusting other clocks.
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No, IANEE, but let me guess:
- mcd ddr
- mcd internal
- mcd cache
- mcd-gcd link
- gcd display-out
- gcd front-end
- gcd shaders
- gcd command processor
- gcd video codecs
- gcd dma
The fact it can achieve very high clocks on irregular workloads (blender?) where the CUs might be stalling a lot (i.e. not consuming as much power..) could suggest that it is using more power than expected.
OTOH on gaming workloads clocks are lower because it's much better utilized and it's more likely to be power limited.
OTOH on gaming workloads clocks are lower because it's much better utilized and it's more likely to be power limited.
460w lol
Poor amd. with zen4, they lost the ability to make fun of intel making hot chips and with rdna3, lost the efficiency bragging.
DavidGraham
Veteran
Add from 30w to 50w on top of this, as software doesn't read AMD's TBP in it's entirety, unlike NVIDIA.
See here:
Power consumption for GPUs
Igorlab posted some major information on power consumption values for AMD and NVIDIA GPUs. As evidently they differ quite substantially on how they do their measurements. Igor used special equipment (shunt measurements/oscilloscope) to measure power consumption from the cards externally to...
forum.beyond3d.com
hoom
Veteran
You know that has to be built into the hardware right?
I mean maybe they intended it to be a 1:1 ratio across the clock boundary or maybe it was supposed to be closer to a 2:1 (1:2?) but I don't imagine they built that capability into it just for shits & giggles.
DavidGraham
Veteran
AMD said exactly this: decoupled clocks with front-end running at 2.5GHz and shaders running at 2.3GHz. That gets 15% frequency improvements and 25% power savings.
So a mere 200MHz difference can save 25% of power? That's a HUGE difference. I think the key to understanding the power characteristics of RDNA3 is in understanding how this difference actually materizlized, it wasn't necessary in RDNA1/RDNA2, or even in the power hungry Vega, so why now?
In Blender, It could also be downclocking memory too to achieve sustained high core clocks.
davis.anthony
Veteran
And my question is why run the front end faster in the first place? They've never done it before, in fact I can't think of any GPU that's done it before and the only memory I have of split clocks is Nvidia running the shaders at a higher clock on their DX10 cards.
If the front is good enough to keep the shaders fed in the first place there should be no need to run them higher so why are they?
Maybe that's where the problem lies, the front end just isn't big enough for the rest of the GPU.
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This statment is not logical. It make sence when the Frontend is not delifering enough content for the shaders. Of cause than you see big efficenty gains when the shader are down clocked. But we do not know how good the shaders are scaling with power.
It is intersting the old frontend was scaling realy good if you look at the rasterizer power. Only the Mesh Shader are not satisfying.
AMD Radeon RX 7900 XTX review: rise of the chiplets | Club386
AMD rips up the rule book by moving premium graphics to a chiplet design. We tell you if this risky strategy has worked.
www.club386.com
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Add from 30w to 50w on top of this, as software doesn't read AMD's TBP in it's entirety, unlike NVIDIA.
See here:
Power consumption for GPUs
Igorlab posted some major information on power consumption values for AMD and NVIDIA GPUs. As evidently they differ quite substantially on how they do their measurements. Igor used special equipment (shunt measurements/oscilloscope) to measure power consumption from the cards externally to...
Another AMD thread derailed and bombed by the usual suspects.
Man from Atlantis
Veteran
Some people experiencing thermal problem.
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