

Ask HN: Why aren't there multi-cpu laptops? - benologist


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informatimago
What for? There are multi-core CPU laptops. Why would be the purpose of
multiplying ceramic cases inside the computer?

Also, remember that distance = time*c, if you put part of the electronics 5 cm
away on a separate chip, then those transistors will try to talk to the
transistors on the other chip, you will introduce a delay of distance/c, about
0.17 nanosecond for 5 cm, double that for an answer.

No, progress goes the other way: integrate more into a single CPU. Check
computers like the Raspberri Pi, or the latest Apple MacBook
[http://www.apple.com/macbook/](http://www.apple.com/macbook/)
[http://www.digitaltrends.com/computing/new-macbook-
smaller-t...](http://www.digitaltrends.com/computing/new-macbook-smaller-than-
raspberry-pi/) which has everything, multi-core CPU, graphic card, RAM, SSD
disks, etc, on a single board no bigger than a smartphone.

~~~
benologist
The Core M stuff was why I was wondering - cpu performance is taking a step
back, couldn't multiple chips compensate for that?

~~~
PaulHoule
Core M was a step back on performance but that was deliberate. For better or
worse, when Core M was conceived, Intel thought we were going towards tablets
and tiny laptops so they focused on that market.

They had horrible teething pains with the 14mm process which meant that
Broadwell was late and also expensive (i.e. expensive tablets and tiny
laptops) but they'll probably have better next with the release.

------
TheAdamist
Eurocom makes a 12-core xeon mobile server. Theres a battery but its used as a
UPS rather than how a normal laptop works.
[http://www.eurocom.com/ec/productsg(6)ec](http://www.eurocom.com/ec/productsg\(6\)ec)

------
Someone1234
Name a use-case for one...

If there is a use-case (and frankly I am sceptical) then that use-case must be
so specific that there isn't mass-market appeal.

Plus batteries suck and many laptops, even high end, have overheating
problems. Two or more CPUs are only going to make that problem significantly
worse.

~~~
benologist
All the reasons we use computers with > 2 cores is the use-case for it.

~~~
Someone1234
But most common computing applications aren't CPU-bound, they're IO bound, or
in some cases GPU bound. CPUs haven't really been a bottleneck for quite a few
years.

~~~
benologist
We also multitask and use lots of software where the CPU _is_ a bottleneck
like browsers, compilers, virtualization etc.

~~~
Someone1234
Unless you're running a dual core i3 from a few years ago I doubt a browser is
going to bottleneck on your CPU. Virtualisation is typically IO bound.

------
feld
Multi-socket computers are not magically faster. In fact, they're often
slower.

It's more important to pack as many cores as possible into a single package.

------
PaulHoule
'Cause then you would need multiple batteries.

~~~
benologist
Why wouldn't it just be trading existing battery time - which is getting to be
a lot of hours - for more power?

~~~
PaulHoule
If you're at the point where you want to spend more money and get a more
powerful machine, the economics are in favor of getting a desktop machine.

Removing a lot of heat in a small form factor is a tough problem, which would
mean expensive engineering work.

