No I reacted to this too - ferromagnetism is one common magnet sure, and I was thinking "the other is electromagnets, in motors". And then it came as "antiferromagnets". Bisarre.
Even if the FX is notionally "free" they pick the rates. So they can set those rates to generate exactly the same profit for them as with fees.
You will probably not see rates that are even competitive with a dodgy FX cash place at an airport, let alone with the numbers you've seen on financial networks for what FX transactions by banks cost, but you feel happy because there was "no fee".
>> Your bank may or may not use the rate indicated by this calculator to bill you
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(As a side note: the fine print follows up with this:
>> If your transaction is converted by the merchant or ATM operator, the exchange rate indicated by this calculator will not apply.
Don't ever let a merchant or ATM do foreign currency conversion for you. They charge astronomically high fees without exception. Pay in the foreign currency and let your card do the conversion.)
Huh. I wonder how long that's been true. I guess I haven't been to America since last century, but I could have sworn I had zero fee but unreasonable FX rates when I was in Poland which can't have been more than 25 years ago.
> You will probably not see rates that are even competitive with a dodgy FX cash place at an airport
You're crazy.
I have a Capital One account because they advertised "no foreign transaction fees". I checked on my foreign-currency payments and was always charged an amount that looked eerily similar to "1% more than you would have paid at the published exchange rate", so it's not clear to me why they say "no fee" and not "1% fee".
But the 1% fee that they actually have is very reasonable. An airport stall is in an entirely different league.
This is flat out incorrect. It's actually quite difficult to get a cash FX rate that's even close to as good as the standard credit card FX rate, which is also set by Visa/MC and not the banks.
Where the banks do get their pound of flesh, though, is the foreign transaction surcharge, which is often around 3%. No-fee cards exist but you need to look for them. And a whole new set of charges applies to doing a foreign cash advance on a credit card.
This is misleading. Banks put a fee on foreign transactions, many do this even if the transaction is in the card's native currency.
The card companies always add a margin to FX conversions, usually in the 0.5% range. This is fairly benign since the market rate can move between the transaction and the settlement, so sometimes you save money.
I think this is generally mitigated: When traveling, people use the card that doesn't have this fee. You have cards A and B. Has a fee; B doesn't. At home you use either. When traveling, you use B.
Is that actually the silicon that's on top of a cpu?
I've always assumed the silicon is super thin - "wafer" thin. And then some material is added where the bonding wires etc are embedded in and the pads or pins are attached to.
For sure it's like this on newer CPUs, where there is not a single piece of silicon bit rather multiple ones with interconnect between them.
Chips are made from silicon wafers that are ~0.8mm thick. The transistor layer is built on one side of the wafer (because the transistors need to be built from epitaxial silicon, that is, where all the atoms are neatly arranged, and you cannot deposit a perfect epitaxial layer). Then the metal layers are built on top, by depositing copper and dielectric (traditionally silicon dioxide, that is, glass, but these days some more exotic stuff is used too).
Then that chip is flipped around, so the transistors and metal layers face the pcb. Most of the chip on the upside is just bulk silicon, and there for structural and heat spreading purposes, it's not needed for operation.
When chips are built out of multiple stacked layers, typically they thin the chips that go below and leave a thick bulk layer on the topmost one. IIRC, for some AMD chips they needed to use a separate, unprocessed bulk heat spreader layer for bonding reasons.
I would guess that the effective layers are super thin. But such super thin parts do not have much structural integrity. So you leave material under it so that you can handle it. And then just drill to those parts as needed.
No, that’s the die sawed out of a wafer. Those are wafer-thin, i.e. about 0.8mm. On some newer CPUs the wafer is ground down to improve thermals. In normal C4 packaging like here the active layer is sandwiched between the metal layers (which sit on the interposer PCB) and the bulk silicon (95% of the thickness upwards, to the camera). Silicon is not a great heat conductor.
There was just this video [0] yesterday showing the whole process for a GaN LED, it's fascinating how crude the post processing can be in contrast with the ultra precise etching and layering.
On the bottom [0], youtuber/cooling specialist/tuner der8auer did an interview with an intel engineer a few years ago. One of the points they bring up is that it's not a pure gain to have less silicon between the logic and the next interface to another material conducting heat away as the silicon itself acts as a conductor/spreader, i.e. sideways as well as upwards, so there's a balance.
(I do not hold phd in magnetics)