On Fri, 2006-11-17 at 03:57 -0800, Tobias wrote:
I just recently purchased a Macbook Pro, Intel Core Duo 2GHz, 512 MB RAM.
After looking through several articles in this forum I found the link to the
R Mac Wiki. I am not that tech-savy but it appeared to me that this link,
http://wiki.urbanek.info/index.cgi?IntelMacR
describes how to install R on a Intel Mac Core Duo to utilise the two cores.
I have also downloaded and installed the universal binary from the CRAN
website. My question now is whether the universal binary package already
sets up R on my Mac in such a way that allows for the utilisation of the two
cores or whether I have to go through the tutorial article of the R Wiki?
I just ran some code that took about 8 hours on my old Windows machine
(Pentium 3, 2.7 GHz, 1GB RAM) to complete on the Mac and it appears to be
roughly 50% slower. That makes me wonder, of course, whether both cores are
being utilised!
Could someone please advice whether I should go through the Wiki article to
set up R or whether it already had been set up properly through the
universal binary package?
Many thanks
Tobias
Having just been indoctrinated into the world of Macs by purchasing a
new Core 2 Duo MacBook (2.0 Ghz) for my 22 year old daughter this week
to replace a failing Dell Winders laptop, some comments:
1. Unless your code is specifically set up to be parallelized, the
presence of dual cores won't make much of a difference.
2. The key difference here is likely to be that your Windows system had
1 Gb of RAM on it versus having only 512 Mb of RAM on your Mac. This
will force your Mac system to be swapping to disk more than what likely
occurred on your old system. Swapping will always slow things down.
3. With respect to disk swapping, depending upon the speed of the disk
you had on the Windows system, the MacBooks have comparably slower hard
drives. The standard drives are 4800/5400 rpms, with only the 100 Gb HD
on the new Core 2 Duo Pros being 7200 rpms. So data transfer rates when
you are swapping will be notably slower, especially if you had a 7200
rpm HD on the windows system.
I got 1 Gb of RAM on my daughter's MacBook (which was standard on the
black model). Also, on the regular MacBook's, video RAM is shared with
system RAM, so you loose about 80 Mb (plus or minus). On the Pros, you
have dedicated VRAM so this should not be an issue. However, 512 Mb of
system RAM is pretty small by today's standards.
I would give serious consideration to upgrading to 1 Gb of RAM on your
new Mac.
Lastly, there is a r-sig-mac list. More info here:
https://stat.ethz.ch/mailman/listinfo/r-sig-mac
HTH,
Marc Schwartz
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