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AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

arstechnica.com

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Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#61

Post by spockz »

EnPissant wrote: post #39
monster_truck wrote: post #29

The extra cache doesn't do a damn thing (maybe +2%) The lower leakage currents at lower voltages allowed them to implement a far more aggressive clock curve from the factory. That's where the higher allcore clock comes from (+30W TDP) I'm not complaining at all, I think this is an excellent way to leverage binning to sell leftover cache. Though if I may complain, Ars used to actually write about such things in their…

It's very workload dependent. It certainly does more than 2% on many workloads. See https://www.phoronix.com/review/amd-ryzen-9-9950x3d-linux/10 > Here is the side-by-side of the Ryzen 9 9950X vs. 9950X3D for showing the areas where 3D V-Cache really is helpful: Coincidentally, it looks they filtered to all benchmarks with differences greater than 2%. The biggest speedup is 58.1%, and that's just 3d vcache on half th…

I think GP was saying that the additional 3D cache on this chip compared to the standard x3d isn’t going to do much.

I’m curious to see whether the same benchmarks benefit again so greatly.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#62

Post by sspiff »

Aurornis wrote: post #43
magicalhippo wrote: post #25

Probably fun for those who already bought DDR5 memory... still kicking myself for not just pulling the trigger on that 128GB dual stick kit I looked at for $600 back in September. Now it's listed at $4k... Meanwhile I hope my AM4 will chug along a few more years.

> Now it's listed at $4k... You can buy 128GB of DDR5-6000 with a 9950X3D (not this newest X2 version, but still a $699 CPU) and a motherboard and a case for $2800 right now: https://www.newegg.com/Product/ComboDealDetails?ItemList=Com... If you don't need 128GB, there are quality 64GB kits for under $700 on Newegg right now, which is cheaper than this CPU. If someone needs to build something now and can wait to upgr…

I bought 192GB (4x 48GB) of DDR5-6400 for 299 euro in September but returned it because I couldn't get 4 DIMMS to run at decent speeds in the system.

6 or so weeks after I returned it the kit was listed at 1499.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#63

Post by disillusioned »

snvzz wrote: post #50
magicalhippo wrote: post #25

Probably fun for those who already bought DDR5 memory... still kicking myself for not just pulling the trigger on that 128GB dual stick kit I looked at for $600 back in September. Now it's listed at $4k... Meanwhile I hope my AM4 will chug along a few more years.

I am glad I decisively ordered 96GB (2x48) DDR5 ECC back in June, alongside the 9800x3d. I hope this is still enough for the planned upgrade to Zen7 in 2028.

Same... got 2x48 DDR5 for $304 back in February of 2025. Equivalent kits are going for $900-$1,100. Madness.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#64

Post by DeathArrow »

magicalhippo wrote: post #25

Probably fun for those who already bought DDR5 memory... still kicking myself for not just pulling the trigger on that 128GB dual stick kit I looked at for $600 back in September. Now it's listed at $4k... Meanwhile I hope my AM4 will chug along a few more years.

>Meanwhile I hope my AM4 will chug along a few more years.

I am fine with my 2 year old 128GB DDR4 for now. I will just upgrade the 14700K to 14900KS CPU and wait 2 more years.

Judging by the benchmarks newer CPUs aren't much better for multithreading workloads than 14900KS anyway, so it doesn't make a lot of sense to upgrade to newer CPUs, DDR5 and a new mobo.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#66

Post by bell-cot »

spockz wrote: post #61
EnPissant wrote: post #39

Earlier quoted context omitted.

It's very workload dependent. It certainly does more than 2% on many workloads. See https://www.phoronix.com/review/amd-ryzen-9-9950x3d-linux/10 > Here is the side-by-side of the Ryzen 9 9950X vs. 9950X3D for showing the areas where 3D V-Cache really is helpful: Coincidentally, it looks they filtered to all benchmarks with differences greater than 2%. The biggest speedup is 58.1%, and that's just 3d vcache on half th…

I think GP was saying that the additional 3D cache on this chip compared to the standard x3d isn’t going to do much. I’m curious to see whether the same benchmarks benefit again so greatly.

> I think GP was saying...

Agree. The article's 2nd para notes "AMD relies on its driver software to make sure that software that benefits from the extra cache is run on the V-Cache-enabled CPU cores, which usually works well but is occasionally error-prone." - in regard to the older, mixed-cache-size chips.

> I'm curious to see...

Yeah - though I don't expect current-day Ars Technica will bother digging that deep. It could take some very specialized benchmarks to show such large gains.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#67

Post by alfiedotwtf »

chao- wrote: post #4

Crazy to think that my first personal computer's entire storage (was 160MB IIRC?) could fit into the L3 of a single consumer CPU! It's probably not possible architecturally, but it would be amusing to see an entire early 90's OS running entirely in the CPU's cache.

> it would be amusing to see an entire early 90's OS running entirely in the CPU's cache.

There’s actually already two running (MINIX and UEFI), and it’s the opposite OS amusing - https://www.zdnet.com/article/minix-intels-hidden-in-chip-op...

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#68

Post by bell-cot »

jaimex2 wrote: post #57

Can someone like... boot Windows 98 on these on a system with no ram?!

Conceptually - yes, easily.

But to do it literally - I'm not a low-level motherboard EE, but I'd bet you're looking at 5 to 7 figures (US $) of engineering work, to get around all the ways in which that would violate assumptions baked into the designs of the CPU, support chips, firmwares, etc.

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#69

Post by 2001zhaozhao »

sspiff wrote: post #62
Aurornis wrote: post #43

Earlier quoted context omitted.

> Now it's listed at $4k... You can buy 128GB of DDR5-6000 with a 9950X3D (not this newest X2 version, but still a $699 CPU) and a motherboard and a case for $2800 right now: https://www.newegg.com/Product/ComboDealDetails?ItemList=Com... If you don't need 128GB, there are quality 64GB kits for under $700 on Newegg right now, which is cheaper than this CPU. If someone needs to build something now and can wait to upgr…

I bought 192GB (4x 48GB) of DDR5-6400 for 299 euro in September but returned it because I couldn't get 4 DIMMS to run at decent speeds in the system. 6 or so weeks after I returned it the kit was listed at 1499.

Yeah the only way to run 4 sticks of DDR5 decently is with Intel. It's a bit of a shame that you can't cram enough RAM to run big models.

The most I could get running on 10GB VRAM + 96GB RAM was a REAP'd + quantized version of MiniMax-M2.5

Re: AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip

#70

Post by 2001zhaozhao »

I don't really see a huge reason to buy this other than it being a top-tier halo product.

For gaming, AMD already pins the game threads to the CCD with the extra cache pretty well.

For multi-threaded workloads the gain from having cache on both CCDs is quite small.

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