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Meta reuses old RAM in new servers with custom bridge chip

theregister.com

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Re: Meta reuses old RAM in new servers with custom bridge chip

#11

Post by Lomlioto »

torginus wrote: post #10

With regards to RAM price I never understood the following: A 16GB RAM stick has 16*8=128 billion bits, with 1 transistor per bit, thats still 128B, yet its supposed to cost like $60 before the price hikes? In contrast, a 5090 GPU was $2000 (true it has RAM, but you're paying for the GPU ASIC really, I guess the rest of the GPU was less than $500), it had 93B transistors. GPU transistors are smaller due to the more a…

A GPU Transistor is a lot more complicated than a RAM transistor and the size of these are quite different too. Bleeding edge vs. a known process with know machines and written off machines.

Also you calculate in the machine cost and R&D.

RAM hiked because the demand spiked and these companies are now in power. Before apple and other companies told them the prices and had hardly any money for investment.

Re: Meta reuses old RAM in new servers with custom bridge chip

#12

Post by mschuster91 »

torginus wrote: post #10

With regards to RAM price I never understood the following: A 16GB RAM stick has 16*8=128 billion bits, with 1 transistor per bit, thats still 128B, yet its supposed to cost like $60 before the price hikes? In contrast, a 5090 GPU was $2000 (true it has RAM, but you're paying for the GPU ASIC really, I guess the rest of the GPU was less than $500), it had 93B transistors. GPU transistors are smaller due to the more a…

> So while RAM is a commodity product, this insane price difference didn't make any sense.

Supply and demand coupled with the fact that a RAM fab can't (trivially) output compute chips, and vice versa, a compute fab can't output RAM. It's two completely different supply chains.

Re: Meta reuses old RAM in new servers with custom bridge chip

#13

Post by rmu09 »

torginus wrote: post #10

With regards to RAM price I never understood the following: A 16GB RAM stick has 16*8=128 billion bits, with 1 transistor per bit, thats still 128B, yet its supposed to cost like $60 before the price hikes? In contrast, a 5090 GPU was $2000 (true it has RAM, but you're paying for the GPU ASIC really, I guess the rest of the GPU was less than $500), it had 93B transistors. GPU transistors are smaller due to the more a…

The thing that defines performance of DRAM is AFAIK the capacitor of the bit cells and not the transistor driving it. And also AFAIK the process to create those capacitors is quite unique to DRAM, so you can't just go and use a "logic" process unchanged and produce DRAMs.

Re: Meta reuses old RAM in new servers with custom bridge chip

#14

Post by adastra22 »

torginus wrote: post #10

With regards to RAM price I never understood the following: A 16GB RAM stick has 16*8=128 billion bits, with 1 transistor per bit, thats still 128B, yet its supposed to cost like $60 before the price hikes? In contrast, a 5090 GPU was $2000 (true it has RAM, but you're paying for the GPU ASIC really, I guess the rest of the GPU was less than $500), it had 93B transistors. GPU transistors are smaller due to the more a…

Why would you expect smaller transistors to be cheaper?

Re: Meta reuses old RAM in new servers with custom bridge chip

#15

Post by ismaVQ »

torginus wrote: post #10

With regards to RAM price I never understood the following: A 16GB RAM stick has 16*8=128 billion bits, with 1 transistor per bit, thats still 128B, yet its supposed to cost like $60 before the price hikes? In contrast, a 5090 GPU was $2000 (true it has RAM, but you're paying for the GPU ASIC really, I guess the rest of the GPU was less than $500), it had 93B transistors. GPU transistors are smaller due to the more a…

newer process node are smaller but very expensive compared to mature ones, each wafer from TSMC latest process is costly and with lower yield due to GPU large die size (+700mm2 compared to around 60mm2 per DRAM die)

Re: Meta reuses old RAM in new servers with custom bridge chip

#16

Post by rcxdude »

torginus wrote: post #10

With regards to RAM price I never understood the following: A 16GB RAM stick has 16*8=128 billion bits, with 1 transistor per bit, thats still 128B, yet its supposed to cost like $60 before the price hikes? In contrast, a 5090 GPU was $2000 (true it has RAM, but you're paying for the GPU ASIC really, I guess the rest of the GPU was less than $500), it had 93B transistors. GPU transistors are smaller due to the more a…

Chip fabrication processes are not fungible: GPUs and CPUs might be made on roughly the same process, but DRAM is not (flash is a different process again, as is power electronics, analog electronics, MEMS, etc. And even within those broader categories there are different variations). While there are some overlaps in machines and techniques, a fab set up for one cannot generally switch to the other, and the economics of each process can also be drastically different.

Re: Meta reuses old RAM in new servers with custom bridge chip

#17

Post by herodoturtle »

pjc50 wrote: post #7
rob74 wrote: post #4

Why not go directly to the source article that has a lot more details? https://www.theregister.com/systems/2026/06/29/zuck-saves-me...

Source paper linked is https://aisystemcodesign.github.io/papers/isca26/vistara_cam... From a quick skim, you could think of this as roughly equivalent to shoving a large amount of DDR4 on a PCIe card and using it as a swap space. It's more sophisticated (see CXL protocol), but that gives you an idea of the tradeoffs. It seems there is some OS-level support for moving hot/cold pages between the main fast DRAM and the…

> and contains significant embedded carbon emissions

Hi - thanks for the insightful comment - could you please expand on the above?

Genuinely curious :)

Re: Meta reuses old RAM in new servers with custom bridge chip

#18

Post by lmz »

herodoturtle wrote: post #17
pjc50 wrote: post #7

Earlier quoted context omitted.

Source paper linked is https://aisystemcodesign.github.io/papers/isca26/vistara_cam... From a quick skim, you could think of this as roughly equivalent to shoving a large amount of DDR4 on a PCIe card and using it as a swap space. It's more sophisticated (see CXL protocol), but that gives you an idea of the tradeoffs. It seems there is some OS-level support for moving hot/cold pages between the main fast DRAM and the…

> and contains significant embedded carbon emissions Hi - thanks for the insightful comment - could you please expand on the above? Genuinely curious :)

"a lot of carbon was emitted while making it"

Re: Meta reuses old RAM in new servers with custom bridge chip

#19

Post by gloryjulio »

torginus wrote: post #10

With regards to RAM price I never understood the following: A 16GB RAM stick has 16*8=128 billion bits, with 1 transistor per bit, thats still 128B, yet its supposed to cost like $60 before the price hikes? In contrast, a 5090 GPU was $2000 (true it has RAM, but you're paying for the GPU ASIC really, I guess the rest of the GPU was less than $500), it had 93B transistors. GPU transistors are smaller due to the more a…

RAM is a commodity. It has much less moat to prevent competitions. When the rams flood the market that's when the bubble ends, until the next cycle arrives. Processors are much harder to design and commoditize.

Re: Meta reuses old RAM in new servers with custom bridge chip

#20

Post by tonyedgecombe »

rock_artist wrote: post #3

The interesting part of this "RAM crisis" is similar to other fields where a problem results multiple parties looking for alternative solutions. This yields for exciting ideas or workarounds that might result a post-crisis memory boom (hopefully) also for local machines. 1. Lowest, Apple is evaluating new Chinese manufacturer which means change of supply demand if indeed it has reasonable QA. ( https://www.ft.com/con…

Necessity is the mother of invention.
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