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Yields are the main barrier to single pieces of silicon that big. You have a certain chance of getting a defect per square mm of you chip and as they get bigge
by Symmetry 7y ago
Yields are the main barrier to single pieces of silicon that big. You have a certain chance of getting a defect per square mm of you chip and as they get bigger the chance of a bad defect gets higher and yields go down. Often they'll occur in a place where you can just disable a core or bank of cache and still sell the chip but not always. So yield rates tend to go down as chips get bigger. Also larger chips make less efficient use of the wafer.
Economically, there aren't so many people looking for 1000 cores that it makes sense to put in the NRE to assemble a giant package to put all of that in versus just selling a system that can have multiple sockets. Cooling limits also make spreading out work across multiple sockets a better choice.
- Namrog84 7y agoHow do GPU cores differ in that they have thousands of cores?
- wmf 7y agoThey don't; GPUs have <72 real cores and thousands of marketing cores. And they can disable defective cores so their massive dies are still usable.
- dingo_bat 7y agoMarketing cores lol...
- Symmetry 7y agoAs wmf said, what NVidia calls a "core" isn't something that can issue it's own instructions so it isn't really something you'd normally consider a core, though it does have a PC and can compare its PC against the PC of broadcast instructions to decide if it should execute or not so it's a bit more sophisticated than a simple SIMD vector lane. Maybe on par with an execution port? What's more equivalent to a CPU core would be what NVidia calls an SM and AMD calls a compute unit. These decide which instructions to issue next and broadcast them to the various lanes. You'll have dozens of them in a typical GPU, about the same as the number of CPU cores in the same silicon area.