I have a base model early 2011 MBP 13 that I bumped to 8GB and an SSD. I've been doing some video editing in Premier recently for some shorter clips at 720p and I've not noticed any major memory problems; mine seems to be processor. For instance, my last project had five layers of video, effects, sound and I had to pre-render every time for the preview or the last layer wouldn't play. I also had iTunes, Mail, Safari with nine tabs, and a music rehearsal application in my user, then on my wife's user, which was logged in, had Safari, iTunes, Word, and Excel running. So I think that 8GB is probably enough, BUT that said, I am in the market for a new machine, since my wife has stolen this one, and I am considering 16GB. Even though 8GB seems to be meeting my needs for the most part, the reasons I am considering 16GB is:
- I know I am a heavy RAM user
- I would like this new machine to last me 5 years
- Soldered RAM
- It's base on the model I'm considering
If you are going to replace every 2-3 years, get the 8GB. Chances are if the machines a few years from now need more RAM, it will become standard. In 5 years I may not need 16GB, but if $200 might get me another 1-2 years out of a Mac, I'm willing to pay it as an insurance fee.
On the other hand, you could get the 8GB and if an OS build comes down the road that requires more memory, just don't update to the latest.
If you are not benefiting from the extra RAM within the first year or two, then it is not worth the money. When you reach the point when 8GB is no longer enough, these are the two situations that would happen (one where you bought 8, and the other 16):
If you bought 8GB - Say you get 5 years and then 8GB os no longer supported. You buy a new machine (or continue to run an OS that has not got the newest features). The money you saved on RAM can be put towards this.
If you bought 16GB - You get an extra year or two extra support over 8GB (maybe slightly more). By that time (using the data from the paragraph above, say the 6th and 7th year of the machine), the CPU and GPU are not going to be up to standard (and certainly not for video editing...).
So the extra £160 has got you two extra years (but not really a useful computer for those gained years), but the 8GB allows you to put the £160 aside and be able to upgrade 2 years earlier than the 16GB (and therefor getting you a new CPU, GPU and more RAM than keeping the 16GB machine for 2 years more).
This is all of course only relevant if you are only going to benefit from the extra RAM by increasing the support time of the computer. If you are running a VM or two, you would benefit from 16GB right away, therefor the money is worth spending.
And PS - 8GB of RAM in 2013/2014 iMacs will last way more than 3 years. I'd say 3 years is a good figure of how long 4GB of RAM has before it's only good for basic tasks, but 8GB of RAM has got at least 5+ years of great use before it drags the computer down. Of course, 16GB would have more again.
