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

3 points by benologist 12y ago

PaulHoule 12y ago
'Cause then you would need multiple batteries.
- benologist 12y ago
  Why wouldn't it just be trading existing battery time - which is getting to be a lot of hours - for more power?
  - PaulHoule 12y ago
    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.
informatimago 12y ago
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-than-raspberry-pi/ http://www.digitaltrends.com/computing/new-macbook-smaller-t... which has everything, multi-core CPU, graphic card, RAM, SSD disks, etc, on a single board no bigger than a smartphone.
- benologist 12y ago
  The Core M stuff was why I was wondering - cpu performance is taking a step back, couldn't multiple chips compensate for that?
  - PaulHoule 12y ago
    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 12y ago
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 12y ago
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 12y ago
  All the reasons we use computers with > 2 cores is the use-case for it.
  - Someone1234 12y ago
    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 12y ago
      We also multitask and use lots of software where the CPU is a bottleneck like browsers, compilers, virtualization etc.
      - Someone1234 12y ago
        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.
        deleted 12y ago
        [deleted]
feld 12y ago
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.

3 points by benologist 12y ago

PaulHoule 12y ago

'Cause then you would need multiple batteries.

benologist 12y ago
Why wouldn't it just be trading existing battery time - which is getting to be a lot of hours - for more power?
- PaulHoule 12y ago
  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.

informatimago 12y ago

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-than-raspberry-pi/ http://www.digitaltrends.com/computing/new-macbook-smaller-t... which has everything, multi-core CPU, graphic card, RAM, SSD disks, etc, on a single board no bigger than a smartphone.

benologist 12y ago
The Core M stuff was why I was wondering - cpu performance is taking a step back, couldn't multiple chips compensate for that?
- PaulHoule 12y ago
  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 12y ago

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 12y ago

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 12y ago
All the reasons we use computers with > 2 cores is the use-case for it.
- Someone1234 12y ago
  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 12y ago
    We also multitask and use lots of software where the CPU is a bottleneck like browsers, compilers, virtualization etc.
    - Someone1234 12y ago
      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.
      - deleted 12y ago
        [deleted]

feld 12y ago

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.