Quote Originally Posted by Computurd View Post
thats a terrible reason not to buy a M4, and this thread that you are posting in shows why! You will probably be better in the long run with 25nm. better tech!
Conventional tech wisdom, based on the nature of how flash NAND works, holds that memory cells at 34nm can be written to more times than memory cells at 25nm. I have yet to see anything in this testing that contradicts that. All the testing has shown so far is that 25nm cells can last longer than the typical 3000 p/e c. estimate. So far only 6 TB longer, but longer nevertheless. Without some sort of modification to the technology, I don't expect that the laws of physics relating to floating gate transistors are going to be all that open to negotiation. What I expect this testing to show is that the traditional estimates based on process size are more or less wild-assed guesses.

Toshiba is supposed to be producing both 2 bit and 3 bit per cell 19nm MLC flash NAND by the end of the year. We can only hope that the 3 bit per cell MLC will not end up in SSDs. IMFT is also supposed to be producing 20nm 2 and 3 bit per cell MLC flash NAND by the end of the year. The old write estimates for that process size were around 1500 p/e cycles, but of course neither company is going to be using those estimates. Instead the write endurance estimates are exactly the same as for 25nm cells. What that shows is not that these companies can get around the laws of physics, but that, without testing, they can claim anything they want which serves their marketing purposes.

You may argue that writes to the 25nm memory are already so high that it is not a concern to the average user and that may very well be true, but not everyone is the average user, and some people might like to get more value for their money in terms of a device capable of having more data written to it. Probably a lot more, but we will see. To me, assuming equal write amplification, a 34nm flash NAND device is worth more than a 25nm one. It offers greater value. It is superior technology in the same way that a 22nm CPU is superior technology to a 32nm CPU. For CPUs/GPUs smaller process size is an advantage to both the manufacturer and the end user. For flash NAND memory smaller process size is only an advantage to the manufacturer. For the end user it is inferior technology. It clearly does not do its job as well.

In some very small consumer devices the smaller process size may be worth the tradeoff in write endurance or for mostly read only memory. But for SSDs it really only makes sense from a consumer perspective if we start to see the sort of massive, dramatic price drops that people have been predicting for years. If I am buying a device with half the write capacity it should be half the price to give the same value. That means that if a 34nm 128 GB drive is selling at $2/GB, a 25nm 128 GB drive should be selling for $1/GB. You wouldn't hear any objections from me about the process size then. But I don't think that's going to happen. Even if the full cost savings were passed on to the consumer by both the memory manufacturer and the drive manufacturer during a period of cuthroat price wars, I think the cost savings will be trivial compared to the amount of write endurance lost.

I think that, despite process shrinks, memory prices will continue to be market driven and will fluctuate with the market just as RAM does. Any manufacturing cost savings will be pocketed, mostly by the manufacturers themselves. If you want to get an idea of how much of the cost savings will be passed on to us from a process shrink take a look at the difference in price between a 25nm 120 GB Vertex 3 and the 32nm Max IOPS version. At Amazon right now the standard Vertex 3 is $270 shipped and the Max IOPS is $310 shipped. Of course the Max IOPS offers more than just better write endurance. It is also faster. So the real price difference due to the larger process size is probably less than $20. One also might want to look at the price points and margins Intel maintains on their CPUs for each tick cycle. Their price does not drop significantly each time they do another cost saving "tick" process shrink. The cost savings are not passed on to the consumer. Of course maybe we would see some of that savings if AMD could catch up with Intel and engage in another price war, but certainly the mere fact that the manufacturer saves money does not automatically result in a savings for the consumer.