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Comment by daeken | Hacker News Reader

> A switch to BGA would mean that the processor could no longer be fitted into socket where it could be removed or replaced, and instead would be soldered to the motherboard much like processors for notebooks and tablets are nowadays.

This is completely incorrect. They could solder all the CPUs, but you can absolutely socket BGA chips. Are there any indications that they're going non-upgradable outside of the switch to BGA?

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you can absolutely socket BGA chips

Eh, not really. Well, you can, but it's ugly, expensive, and usually only done for test fixtures and such.

I really don't see why they have to be ugly or expensive. They're absolutely expensive now, but that has a lot to do with the way in which they're used (test equipment is crazy expensive) and very little to do with what they actually are. As for ugly, well, ZIF sockets aren't exactly lovely, they're just really effective.

BGA sockets are only used for prototyping; they're expensive compared to other kinds of sockets.

Are they expensive because of some inherent property, or because they're only used for prototyping and are thus done in small runs? Having spent several hundred dollars on a little plastic BGA socket that could be made for pennies, I'm inclined to say that it's the insanely small production runs right now.

BGA balls are made of solder, and they'll cold-flow under pressure. So any socket meant for durable use in production equipment (as opposed to prototype or test purposes) is going to require a lot of small, delicate, and expensive spring contacts that provide a secure connection with very little force.

Also, sockets in general are perennial problem areas for signal integrity and EMC.

It is probably best to think of the motherboard as a monolithic hunk of material, going forward. Too many reasons for the trend to go in that direction.

I don't know too much about LGAs vs BGAs, but the Wikipedia article mentioned that sockts are "less reliable". How does the reliability compare between BGAs in a socket vs LGAs in a socket? The wikipedia article mentioned that BGAs can move heat around better; is this lost when a socket is used?

I hope Intel doesn't go the socket-less route. This seems like it would alienate the Linux server market for high-reliability servers that depend on CPU hot-plugging. Perhaps this only applies to the consumer market?

Generally, a soldered IC is more physically durable and gets some more heatsinking as a result.

BGAs in a socket fail after about 5 years of not being moved, or maybe a dozen times you move things.

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