Aperture will not run satisfacorily on that Mac with the 1 GB RAM you list. In fact Aperture will probably not run at all.
If you max out the RAM to 3 GB Aperture will run (but slowly) on that MB. I have a backup Aperture setup running on a 2006 C2D 17" Macbook Pro with 3 GB RAM, OS 10.6.8. However my MBP may have stronger graphics than your MB, which is important for Aperture operation.
In general I recommend that folks running legacy hardware stick to legacy OS versions and legacy apps versions. It is a bit of a challenge to figure out which versions are best, and if you uograde too far it can be difficult or impossible to go back. Personally I am running 10.6.8 and Aperture 3.2 on my 2006 MBP and I will not upgrade beyond those versions.
Nikon makes the D5100 with NEF files, not Canon. You do need a version of 10.7 to read D5100 NEF files. IMO anyone going to 10.7 should go to 10.7.4.
An excellent RAM vendor is OWC:
They will also answer questions, provide tools, etc. regarding the feasibility of your RAM upgrade. Great folks that I have bought from for decades.
Upgrading the RAM to maximum is essential. Once RAM is upgraded to 3 GB I believe your Mac will run 10.7.4, and OS 10.7.4 will convert D5100 NEF files with or without Aperture.
Note that in general newer versions of apps and OSs take advantage of more RAM. This is a good thing because RAM is cheap and designing around more RAM improves performance. However it is not so good for old laptops trying to run state-of-the-art images management applications like Aperture. OS 10.7 uses more RAM than previous OS versions, so when running Aperture with only 3 GB RAM I suggest:
• Try to run Aperture by itself. For sure quit apps like browsers when running Aperture.
• Restart before Aperture work sessions to clear possible memory leaks
• and/or switch from 64-bit operation to 32-bit operation (which will make some additional RAM space available). See Switching Kernels:
I believe that with 3 GB RAM it will all work, but my own old laptop is on 10.6.8 so I have no personal experience with 10.7 on an old MB. My 2011 MBP runs Aperture 3.2, OS 10.7.4 and 8 GB RAM and it rocks.
The blunt truth is that to run well - particularly on the latest incarnations of OS X - Aperture really does require 8GB to do well. Yes it will run in 4GB but truthfully not that well. I also endorse SierraDragon's recommendation of OWC. I've done business with them for years and have found them to be smart, honest, and go above and beyond for customer satisfaction. OWC has developed several products that allow the installation of more RAM than orginally specified though I don't know if your particular model is included.
Thanks you all for your answers and advices it is really usefull. I think that the first important thing is like you all said to increase my RAM. It is the first time I am limited by my computer because usually I use for Internet, iPhoto and Microsoft and that it. But now with my new camera I really want to read my *.NEF files.
I will maybe start just with the Nikon viewer NX2 and see if I can wait a little for Aperture. I will buy a new computer in one or two years.
@SierraDragon: I have check Apple tech document before ask you the question but I am not really familiar with all this so it was hard to me to guess if it will run properly or not.
Thanks again ! =)