Would I benefit from a quad core laptop?

Hi,

I'm currently thinking about getting a new "light" laptop such as the Lenovo X220. I would mainly use it to do some statistical computing in R which involves heavy CPU use. As far as I know R is not a multi-threaded application so I would not benefit from multi-cores directly. However I once manually launched two sessions of R in windows and I could run the same analysis in parrallel which was significantly faster than a single session. The laptop was equipped with a dual-core processor and each of the R threads used 50% CPU resources (a single R session actually couldn't used more than 50% by the way...).

Now obviously I wonder whether I could start R 4 times on a quad core and have the analysis work even faster??? Would that actually work this way? Is there anyway to have one session of R use 100% CPU or is it possible to automate the splitting of R sessions?

I know that currently there is no quad core in ultraportables such as the X220. But I may wait for ivy bridge and configurable TDP as this is supposed to bring quad cores in small form factors. So the question is: would I benefit from a quad core if I wait for ivy bridge or is there no real benefit for my use...and so I could get a X220 right now?

Thanks for input

PS: I'd compare a i7 2620M (dual core 2.7Ghz, turbo up to 3.4Ghz) with a i7 quad core with a base frequency of about 2.0Ghz or more and a turbo above 3Ghz (possibly ivy bridge).

 

If you have a task that can be split across independent sessions and you have enough RAM to keep each session satiated then yes, that is how it will work. Note that if you do not have the RAM, you will force the machine to use the hard drive instead and that is much, much, slower.

In what context are you using R? In Linux, you can write a shell script that does this. The same is true for Windows, but you'd have to use it from a command line rather than a graphical interface.

If you have a parallelizable task, then yes, you will benefit.

 

Thanks for your answer! I'd be interested to know which command i should use in windows to split 2 R sessions? I use the R graphical user interface in win7 ultimate but i also use an editor (tinn-r) to write my code and send it to R.

 

You can assign programs cores from the processes tab in task manager. Just right click and set affinity.

 

Actually in the meantime i found a nice R package for parallel computation: snowfall. Seems to do the trick as my dual core now runs 100%

 

Then you would definitely benefit from a quad .

 

Ok then i'll try to wait for ivy bridge and the new 35W quad core that's supposed to come. May be available on something such as a thinkpad t430 or x230. Thanks!