AMD's Ryzen 9 9950X3D2 Dual Edition crams 208MB of cache into a single chip (arstechnica.com)

by zdw 170 comments 311 points
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170 comments

[−] magicalhippo 49d ago
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.

[−] Aurornis 49d ago

> 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 upgrade RAM in a year or two, 32GB kits are in the $370 range.

I don't like this RAM price spike either, but in the context of building a high-end system with a 16-core flagship CPU like this and probably an expensive GPU, it's still reasonable to build a system. If you must have 128GB of RAM it can be done with bundles like the one I linked above but I'd recommend waiting at least 6 months if you can. There are signs that prices are falling now that panic-buying has started to trail off.

128GB of RAM should not cost $4K even in this market.

[−] adrian_b 49d ago
$2800 is still a huge price in comparison with the last year.

Last summer, a 9950X3D + motherboard + cooler + 128 GB DRAM + VAT sales taxes was the equivalent of $1400 in Europe, where I live.

That's half of your quoted price. That was without case and PSU, but adding e.g. $200 for those would not change much.

[−] alias_neo 49d ago
In January I upgraded my desktop, 9950X3D £600, 64GB DDR5-6000 £600, MSI MAG Tomahawk X870E £300, Samsung 990 Pro 4TB £350, Asus Prime 9070XT £580. I spent a another £250 on PSU and cooler and reused my case (Phanteks Evolv Enthoo TG, beautiful case but horrible cooling. Will cut some holes in it and if it doesnt work out look for something with more airflow).

The RAM price was already inflated at that time, and the same kit is now £800, but in October or earlier last year I'd have saved possibly the cost of the CPU/GPU on the whole thing, but now it's be about the cost of a CPU/GPU more expensive.

On a side note for anyone not aware, 9950X3D isn't the best choice for pure gaming, 9850X3D is cheaper and marginally better, also I went with 2 sticks of RAM kit, 4 sticks is much harder to run at the advertised speed (6000) which is actually an overclock.

Im a dev and a linux user/gamer hence my choice of CPU/GPU.

[−] sqquima 48d ago
Very similar config, but I bought a second pair of ram. Running 4 sticks at 3600. Also, the LAN port of the motherboard stopped working after a week, so I had to buy an Ethernet card
[−] alias_neo 48d ago
Ouch, were you not willing to RMA for that ethernet port? I wouldn't be too pleased after only a week if parts of the board stopped working.

I don't really want to run my RAM that slow which is why I'll probably stick with two sticks.

[−] Aurornis 49d ago
Yes of course. We all know prices are up.

I commented because someone thought that $4K was the going price for 128GB of RAM, which is way too much even with the demand crunch.

[−] adrian_b 48d ago
Due to the high prices of DRAM and SSDs they now are the greatest fractions of the total price of a computer.

In January I was forced to upgrade an ancient Intel NUC, by replacing it with an Arrow Lake H based ASUS NUC. The complete system with 32 GB DRAM and 3 TB SSDs has cost EUR 1200, including VAT sales tax.

The distribution of the price was like this:

  Barebone mini-PC:   41%
  32 GB DDR5 SODIMMs: 26%
  2 TB PCIe 5.0 SSD:  24%
  1 TB PCIe 4.0 SSD:   9%
Since then, the prices of DDR5 and SSDs have continued to increase, so now the fraction spent for memory would be even higher than 59%.

Before 2026, for so small amounts of memory its cost would have been much less than the rest of the system.

[−] sspiff 49d ago
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.

[−] 2001zhaozhao 49d ago
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

[−] mort96 48d ago
Got it running with 4800MT/s and literally 30 minute boot times in an AM5 machine. The 30 minute boot time could be worked around by enabling the (off-by-default) memory context restore option in BIOS, but it really made me think something was broken and it wasn't until I found other people talking about 30 minute boot times that I stopped debugging and just let it sit for an eternity.

It's so bad. I don't get why they sell AM5 motherboards with 4 RAM slots.

At least that system has been running well for like two years. But had I known that the situation is so much more dire than with DDR4, I would've just gotten the same amount of RAM in two sticks rather than four.

[−] WD-42 49d ago
I’m running 128gb on a 9550x now with 4x32gb sticks and it’s terrible. It’s unstsable, post time is about 2 minutes (not exaggerating)and I’m stuck at a lower speed. I’m considering just taking 2 of the sticks out and working with 64gb and increasing my swap partition. The nvme drive is fast at least.

This is my first time off intel and I have to say I don’t understand the hype.

[−] jodleif 49d ago
Threadripper is a good alternative. No point having a lot of dual channel ram for LLMs, too slow
[−] magicalhippo 49d ago
No such bundle deals where I am. Absolute cheapest DDR5 128GB kit around is 2 sticks of 5600 64GB for $2k.

Cheapest 64GB kit is $930.

The kit I was oh-so-close to buying was two 6400 64GB sticks.

Not gonna buy now, not that desperate. I have a spare AM4 board, DDR4 memory and heck even CPU, I'll ride this one out. Likely skip AM5 entirely if something doesn't drastically change.

[−] nicman23 49d ago
that bs of you don't need 128 are toxic. what if you want to upgrade from ddr4 and you already have 128?
[−] jofzar 49d ago
I really want a x3d because a game I play is heavily single threaded, I have the income and the financial stability but I can't in any good conscious upgrade to am5 with the ram prices. It's insane
[−] tarangsutariya 49d ago
Wonder how much sales amd and intel are losing because of tight DDR5 supply
[−] snvzz 49d ago
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.

[−] jmyeet 49d ago
After randomly breaking the AM4 CPU and motherboard in my 4 year old PC last year and seeing that at the time I'd spent almost a new PC to get new parts and rebuild it. Less if I wanted to do a complete rebuild myself but I'm over building PCs. I've done that for years.

It was an expensive mistake as I bought a few options to experiment including a NUC and an M4 Mac Mini but eventually bought a 9800X3D 5070Ti PC for <$2 and for no reason in particular I bought a 64GB DDR5-6000 kit for $200 in August or so. I checked recently and that kit is pushing $1000. I also bought a 4080 laptop and bought a 64GB kit and an extra SSD for it too last year.

That's pretty lucky given what's happened since. I don't claim any kind of foresight about what would happen.

I do kind of want to take the parts I have and build another AM4 PC. The 5900XT is not a bad option with 16 cores for ~$300 but my DDR4 RAM is almost useless because the best deals now are for combos of CPU + motherboard + RAM at steep discounts.

You can get some good deals on prebuilts still. Not as good as 6+ months ago but still not bad. Costco has a 5080 PC for $2300. There's no way I'm going overboard and building a 128GB+ PC right now.

I've seen multiple RAM spikes. We had one at the height of the crypto hysteria IIRC but this is significantly worse and is also impacting SSDs. I kinda wish I'd bought 1-2 4TB+ SSDs last year but oh well.

We're really waiting for the AI bubble to pop. Part of me think sthat'll be in the next year but it could stay irrational substantially longer than that.

[−] DeathArrow 49d ago

>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.

[−] throawayonthe 49d ago
oh wow you weren't joking: https://pcpartpicker.com/products/memory/#xcx=0&b=ddr5&Z=131...

(cheapest at $1240 USD)

[−] tom_alexander 49d ago

> Probably fun for those who already bought DDR5 memory

Nah, those of us who already bought DDR5 memory also already bought decent CPUs. Dropping another $1k for these incremental gains would be silly. It'd make a lot more sense if DDR5 had been around longer so that people had the option to make generational upgrades to this CPU but DDR5 on AMD has only been around for Zen4 and Zen5.

[−] chao- 49d ago
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.

[−] senfiaj 49d ago
Back in 2004 my PC RAM was 256. My relative's laptop had 128. That's crazy when a modern CPU cache can theoretically host an OS (or even multiple OSes) from early 2000s.
[−] monster_truck 49d ago
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 articles instead of speculate in a way that suspiciously resembles what an AI would write.

[−] nexle 49d ago
Breakdown of the (semi-clickbait) 208MB cache: 16MB L2 (8MB per die?) + 32MB L3 * 2 dies + 64MB L3 Stacked 3D V-cache * 2

For comparison, 9950X3D have a total cache of 144MB.

[−] pwr22 49d ago
I'm interested to know if the L3 cache all behaves as a single pool for any core on either CCD, whether there's a penalty in access time depending on locality or whether they are just entirely localised.
[−] abcde666777 48d ago
A year ago I swapped out a 5800x for a 5800x3d to get more stable frame rates in Counterstrike 2. Made a sizable difference, especially to 1% lows, so these large caches can clearly be a big boon. Granted it's also obvious the game is poorly optimized, the gains look less significant for most other titles.
[−] erulabs 49d ago
9950X3D2? AMD, who is making you name your products like this? At some point just give up and name the chip a UUID already.
[−] Readerium 49d ago
Can someone explain if the 3D Vcache are stacked on top of each other or side by side.

If they are stacked then why not 9800X3D2?

[−] 2001zhaozhao 49d ago
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.

[−] jaimex2 49d ago
Can someone like... boot Windows 98 on these on a system with no ram?!
[−] rietta 48d ago
I am so grateful that I bought my 128 GB ram kit in January of last year for my own 9950 upgrade. We just built my dad a 7000 series to replace his old AM4 (2017 build) and 32 gigs DDR five was nearly the same price at Micro Center that I paid last year. I was able to gift him an Nvidia 1060 discreet graphics card so that he could continue to run his two monitors. The newer motherboards have much less on board capability for that.
[−] kristianp 48d ago
Nobody adds L1+L2+L3 like that, because L1 stores a subset of L2 and L2 stores a subset of L3. Just say 192MB of L3.
[−] tw1984 49d ago
that is larger than the HDD of my first PC.
[−] SubiculumCode 48d ago
Oh man. I am running computations on my server that involve computing geodesic distances with the heat method. The job turns out to be a L3 cache thrasher, leaving my cpus underutilized for multi worker jobs .... 208mb instead of my 25 per socket sounds amazing
[−] fc417fc802 49d ago
Given that the dies still have L3 on them does this count as L4 or does the hardware treat it as a single pool of L3?

Would be neat to have an additional cache layer of ~1 GB of HBM on the package but I guess there's no way that happens in the consumer space any time soon.

[−] varispeed 48d ago
I know the prices of RAM are high, but 256GB RAM limit seems like omission. If they supported at least 512GB in quad or eight channel that would be something worth looking at for me. I know there is Threadripper but ECC memory is out of reach.
[−] DeathArrow 49d ago
My first computer had 64KB of RAM. My first PC had 8MB of RAM.
[−] sylware 49d ago
With the best silicon tech, in R&D, what would be the maxium static RAM(L1 cache) you could really slap to a 8 core CPU? (Zero DRAM).
[−] renewiltord 49d ago
I have a gigabyte of cache on my 9684x at home!
[−] electronsoup 48d ago
Whenever I see a chip like this, I think "why wont my company let me use a decent computer"
[−] MaximilianEmel 48d ago
They should allow it to function without any external RAM.
[−] Jotalea 48d ago
so you're telling me I can (theoretically) have a full Alpine Linux installation in just the CPU? I'm impressed
[−] swarnie 49d ago
Factorio mega basing just found a new ceiling.
[−] throwaway85825 49d ago
It's disappointing that they had this for years but didn't release it until now.
[−] jeremie_strand 49d ago
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[−] jeremie_strand 48d ago
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[−] qmr 49d ago
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