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AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

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Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#211

Post by jeffbee »

bee_rider wrote: post #210
jeffbee wrote: post #128

Earlier quoted context omitted.

Yeah, it definitely depends on your use case. In my opinion the only reason to get the K or KS SKU is that you want, and are sensitive to, the extra speed bins you get on the 2 magic P-cores. The KS is a full 10% faster on single-threaded, compute-bound workloads. That's like importing the next generation CPU from the future and it is worth it for some use cases. Even with 1 core running at 6GHz you won't blow out a…

Ah, so tune down the E-cores to provide headroom for the P-cores? That seems like a pretty reasonable thing to do.

I also approve of capping the max clock speed on the E-cores because they don't get much more work done when boosting, yes.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#212

Post by cma »

hajile wrote: post #106
cma wrote: post #86

Earlier quoted context omitted.

SRAM burns more power and uses more die space than DRAM Some do make them bigger and bigger, like the whole-die cerebras AI chip.

That's only partially true. SRAM doesn't need to be refreshed constantly like DRAM, so SRAM will use LESS power when not switching. We think it's different because something like L1 cache is CONSTANTLY switching. It should be noted that the power cost per GB still isn't worse than DRAM, but there's way more data being transferred. Once you reach L3/L4 cache, it's not switching nearly as often and the actual total pow…

Interesting. Why with SRAM is switching so much more power consuming than just maintaining? I thought with a flip flop every gate is used on pretty much every cycle while it feeds back on itself.

I would have thought reading/writing SRAM is much more expensive than idling it not because of the cost of toggling the flip-flop, but all the cache coherency stuff associated with making a change in multicore.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#214

Post by IshKebab »

hajile wrote: post #136
IshKebab wrote: post #99

Earlier quoted context omitted.

Die space. There's a maximum reticle size. You can't make chips bigger than that without using multi-chip techniques like wafer scale integration, chiplets and so on. If you do a full reticle chip and use most of it for memory you can get about 1GB of SRAM. But that would also be extremely expensive.

It's not quite as bad as you might think (though it is bad). TSMC N5 is 0.021um per SRAM cell in high-density configuration (still going to be 5-10x faster switching than DRAM). That's about 47.62 bits/um. With 1,000,000 um2 per mm2. EUV reticle limit is 858mm2. That amounts to 40,857,142,857 bits or about 4.756GB. That's almost exactly 250 dies per wafer. TSMC N5 wafers cost $17,000 or roughly $68 per chip (you can…

> That's almost exactly 250 dies per wafer

You might want to check your maths on that. It's more like 30 maximum reticle size dies per wafer IIRC. Just the area based limit is pi * 150^2 / 858 = 82, but you obviously lose a load because dies are rectangular and wafers are circular.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#216

Post by mldbk »

mmis1000 wrote: post #164
Salgat wrote: post #158

I'm not a fan of how they park the slower CCD, since it means that the scheduler will try to force all processes onto the same CCD (regardless of whether it's for the game), instead of offloading the non-game workloads onto the other CCD. This is an issue if you run background tasks (such as streaming) or have multiple monitors setup for other things like browser etc.

I think I already have similar troubles with that about Radeon gpu. Their driver (or window11 itself) directs all GPU resource into the foreground app aggressively and basically stop the background app from using it. But I am trying to recording the game using obs. This basically make obs unusable if the gpu is near 100% usage. And sometimes it went even wrong, It decides to direct all gpu resource to the browser on…

It is Windows 11 thing. You have to disable GPU scheduling at:

System > Display > Graphics > Default Graphics Settings

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#217

Post by mldbk »

Macha wrote: post #141
TacticalCoder wrote: post #3

Does this 7950X3D have an iGPU? P.S: the table in TFA lists the 7700 as having the same 105W as the 7700X. I think that's a slight mistake and the 7700 is 65W max listed TDP instead. FWIW I'm considering a 7700 for I'm not ultra happy with my 3700X (one of the reason being it has no iGPU and I could find a passive GPU with a NVidia chipset, forcing me to use proprietary drivers in Linux and it's a major PITA for if I…

What do you need the iGPU to render? A desktop or IPMI? Sure, it has one. An actual game? It may as well not. It won't compete with the iGPUs on Intel CPUs or even AMD's APUs.

Probably make a GPU passthru for VM and stay with iGPU within hypervisor

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#218

Post by mmis1000 »

mldbk wrote: post #216
mmis1000 wrote: post #164

Earlier quoted context omitted.

I think I already have similar troubles with that about Radeon gpu. Their driver (or window11 itself) directs all GPU resource into the foreground app aggressively and basically stop the background app from using it. But I am trying to recording the game using obs. This basically make obs unusable if the gpu is near 100% usage. And sometimes it went even wrong, It decides to direct all gpu resource to the browser on…

It is Windows 11 thing. You have to disable GPU scheduling at: System > Display > Graphics > Default Graphics Settings

RX6900 don't even support GPU scheduling at first place. I don't have option like that there unfortunately.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#219

Post by paulmd »

mastax wrote: post #36
Scandiravian wrote: post #8

I wish they'd included the results of the undervolted 7950x in the graphs (aka ECO mode) It's sad that performance benchmarks have made market conditions where the gain of 5% performance is somehow worth 20%-30% extra power consumption (and the noise that follows from that)

The X3D chips do at least have a reduced TDP of 120W vs 170W (except for the 7800X3D vs the confusingly comparable 7700X's 105W). The other thing is that, at least in DIY PC (and botique builders like CyberPower) the "gaming" motherboards universally increase the maximum peak power target and also commonly enable things like all core turbo and precision boost overdrive by default. So unless they specify otherwise, li…

> The other thing is that, at least in DIY PC (and botique builders like CyberPower) the "gaming" motherboards universally increase the maximum peak power target

Worth noting the PPT is higher than the TDP by default - a "120W" AMD chip is actually allowed to boost to 168W continuously, obviously they prefer to advertise the former and have people making comparisons between "120W" AMD and Intel chips running at full boost PPT.

X3D chips are a cut above the rest of the market in terms of efficiency (although this mostly springs from the clock restrictions imposed by the v-cache CCD, which is undesirable and will be removed/mitigated once the technology permits) but in the rest of the lineup this slides them much closer to the Intel line than AMD would prefer people to think about. A 170W TDP 7950X is actually 220W, a 125W 7800X is actually 170W. People reflexively think in terms of AMD's marketing TDPs when making comparisons and don't account for the fact that the chips are allowed by the spec to boost way above that.

And it's been incredibly successful - every single AMD thread there's someone talking about their nice efficient 65W processor and lol unless you turned off the boost (which is separate from just enabling eco!) then no, it's not 65W. Still good, still usually more efficient than Intel, but AMD gave themselves an instant 30% edge on paper with the power of clever marketing and that's always been a significant amount, enough to swing purchases.

That part is not something that gaming motherboards do automatically, and I've never seen one that will enable multicore enhancement-style tuning by default. If you enable overclocking yourself (and enabling XMP/DOCP is considered overclocking since this usually increases VSOC or VCCSA to allow the memory controller to run faster than spec) then all bets are off but by default no, they shouldn't be, just the terminology difference that springs from AMD's marketing trickery around TDP vs PPT. And hey if people end up blaming partners for AMD's spec... that's just good marketing work.

PBO is the setting where you'd see power limits increased and I've never seen that on by default, it's always hidden behind a "THIS VOIDS YOUR WARRANTY AND KILLS YOUR DOG" disclaimer in a separate panel.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#220

Post by sixothree »

mosquitobiten wrote: post #183
sixothree wrote: post #73

Earlier quoted context omitted.

RIP threadripper workstations support.

I think they scaled it down to the actual size of the market which is pretty small and that might look like what you're saying.

They did break some promises here. So it might be a self fulfilling prophecy. But agreed, this is not a huge market.
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