[simoncion]

> If it helps any just think of the costs as buying diamonds.

This is an unhelpful analogy.

Comparing the retail price of diamonds to the retail price of CPUs, RAM boards, and GPUs, I am lead to believe that whatever is used as the substrate for modern high-performance ICs is actually rather cheap. I can -after all- get a reasonably fast combination CPU and GPU for $45.

If we ask the USGS, we discover that in 2003, the price of synthetic diamond suitable for reinforcing saws and drills sold for $1.50->$3.50 per carat. However, large synthetic diamonds with "excellent structure" suitable for -one presumes- processes that rely on the crystal's fine structural properties -just as CPU manufacture relies on silicon wafers with fine structural properties-, sold for "many hundreds of dollars per carat". [0]

One carat is 200 milligrams. An entire Core i3 appears to weigh 26,800mg [1]. Let's be generous and assume that the CPU die is 1/1000th of that weight, or 268mg, or 1.32 carats. Given that CPU manufacture requires a substrate with excellent structure, just how much of a substance that costs many hundreds of dollars per carat can there be in a 1.32 carat device? (Especially when ones of similar weight constructed with similar materials can be had for $45 per, retail?) :)

[0] http://minerals.usgs.gov/minerals/pubs/commodity/diamond/dia...

[1] http://www.cpu-world.com/CPUs/Core_i3/Intel-Core%20i3-2100%2...

[Dylan16807]

Yes, a wafer is something like a hundred dollars, that's not the expensive part.

[simoncion]

I know that the substrate isn't the expensive part. Even a cursory gut-check reveals a claim to the contrary to be bunk.

I felt that a somewhat detailed analysis of the inappropriateness of the analogy was better than a "Nuh uh! You're wrong!" response.

[Dylan16807]

Well the thing is you're analyzing in a way that's both in-depth and shallow at the same time. It doesn't matter that they have 'excellent structure' unless you care about actual wafer costs. Just use diamond prices and dimensions.

[simoncion]

> ...you're analyzing in a way that's both in-depth and shallow at the same time.

I can't really dispute that. I'm no expert in the field.

> Just use diamond prices and dimensions.

Isn't that more or less what I did?

Diamond price per gram depends on the quality of the diamond. If we're gonna address an opinion that includes statements like "Think of the cost of a modern high-performance IC as if it was made of diamonds, because diamonds and silicon are both crystalline structures, and silicon is chemically much like carbon, therefore the substrate manufacturing costs are bound to be very similar." [0], then it seems that we need to look at the cost of high-quality diamonds that are used for their crystalline properties, rather than just for their hardness.

I'm not at all sure, but I would suppose that it would be far more expensive to make one high-quality diamond sheet the size of a silicon wafer than it would be to make a bunch of high-quality diamonds each the size of a CPU die, or maybe cut down a larger one. If it is, then an analysis based just on like-sized crystals would be dramatically unfair. Perhaps you know far more about this than I do? Industrial crystal production is not exactly in my wheelhouse. :)

[0] Direct quote: "Did you know that a silicon wafer is a perfect crystal, structured like a diamond? Silicon is right underneath Carbon in the periodic table, which means it shares the same outer electron shell configuration. Making that ain't cheap." via [1]

[1] https://news.ycombinator.com/item?id=10056870

[Dylan16807]

What I'm saying is: it might be appropriate to look at specific kinds of diamond because of the complexity of lithography and such. But the purity of the wafer doesn't matter because that has nothing to do with chip cost.

That post was wrong about that being a driver of costs, and it's not fruitful to build on that wrongness.

An analogy that leads you to the right conclusion for the wrong reason is a toxic thing.

[simoncion]

Do you mean to say that silicon wafers with higher guaranteed purity are not more expensive than those with lower guaranteed purity? I'm seriously asking; I don't know.

To speak to the rest of your comment:

mozumder made an incorrect argument and backed it up with a dangerously misleading analogy. I attacked the analogy by demonstrating its inappropriateness.

In my most recent post, I have attacked his argument with an analysis of what appear to be the actual costs of the thing he's talking about.

[mozumder]

A wafer cost isn't insignificant. It's still a lot more expensive than aluminum platters in a hard drive, especially when you're dealing with gobs of chips in an SSD.

Add in processing costs and it really becomes a mess.

So, yes, wafer costs matter when you have to produce tons of silicon for an SSD.