Ask HN: Why are flash memory prices going down so much faster than RAM?

MLC is half as expensive as SLC. TLC is 33% less expensive than MLC. QLC is 25% less expensive than TLC and 75% cheaper than SLC. Not to mention transparent compression algos. As the controllers improve you can get more bits of storage from the same amount of flash for free. Longevity and reliability suffers, but hey, cheap SSDs!

Ram only gets cheaper by improvements to semiconductor processes, which also can be applied to make flash cheaper. (Big fat asterisk, those processes are very different.) While improvements to flash that allow more levels per cell can't be applied to ram. The price difference between flash and ram will only continue to grow.

Modern flash is quite "analog". The first company to figure out how to reliably store 32 voltage levels per cell (Five bits. PLC?) will make a quick billion.

Today 2GB/s is considered very good for an SSD but that would be brutally slow for system memory. DDR4 memory is typically 30-60GB/s per bank with the low end being two-channel, the high end being four.

DRAM has also been the subject of aggressive research and development for many, many decades while large-scale production of flash is a relatively recent phenomenon. It's the widespread adoption of smart phones, thinner notebooks, and ubiquitous USB keychain type devices that as pushed it to the volumes it's at now.

There's also the concern that DDR memory must have a very high level of data integrity, bit-flip errors are severely problematic, and it can't wear out even after trillions of cycles. Flash has more pervasive error correction, and while wear is a minor concern, it's still possible to exhaust it if you really, really try.

I'd say the reason flash memory prices are steeply down is the new "3D" process used by Intel and Samsung has been a big game-changer, allowing for much higher density. DRAM has seen more gradual evolution through the last few generations.

I purchased 64GB of DDR3 for <$100 a year ago. Now I the prices are >$100 for 32GB of DDR3. DDR4 prices are idiotic ~$100 for 16GB

I don't think it was ever this cheap

DRAM is also a much more mature technology than flash is, so more of the low-hanging fruit for improvement has already been taken advantage of.

At least at the retail level in the Best Buy where I worked until recently, I watched Solid State drives transition from something only high end computers had to something that was standard even among the lower priced value machines. We had customers complaining about the smaller drive sizes because they were so accustomed to the gigantic storage offered by the spinning disk media at its height in popularity.

I'd love someone with more industry knowledge to chime in though, as my own experience here is pretty limited. This is simply what I've observed in my own corner of the world.

Theoretically RAM could be built that way but it would be much slower. Every cell read/write would need to go through an ADC/DAC, and the noise is much higher due to leakage. This slowness isn't much of a problem for FLASH because its competition was spinning disks that were slow as molasses anyways.

As a second bonus, even on old systems SD card circuits are relatively small (compared to a 5-60" LCD they certainly are). Wafers are round and old wafers are used to manufacture LCD displays, so small chips can be placed around them in the manufacturing process and get really good economics by having lots of manufacturing options.

So same reasons displays are getting cheap, except they're even better. So the race to the bottom is happening pretty fast for SD cards.

Not entirely sure about this. Might be entirely wrong, but I'm not sure how to confirm this.

China has decided to pour in 10s of Billions into the NAND and DRAM industry by 2020, until then the price should very much stable / predictable.

There is some debate about whether HP's chips are "true" memristors or just PCM, but ultimately that's irrelevant to customers as long as they store data.

The telecoms, both cellular and ISP's, are where this is most obvious where the compete in the most incremental way saying its impossible to do anything else. Then, a small play comes in doing what they're doing... sometimes the same way... with more benefit at a tiny fraction of the cost. Suddenly, they can afford to do the same with their existing infrastructure. Real competition would've brought in unlimited plans in cell phones or gigabit in broadband much sooner for similar or lower prices.

The largest vendors of RAM are likely a cartel in practice. It's the best outcome for each of them to not race to the bottom. They don't even need to talk to know that. That they can reinforce it with patents they're more likely to have than the smaller players is icing on the cake.