27" iMac upgrade priorities for Aperture use?
I am about to pull the trigger on a new iMac 27". Current Aperture librabry is about 700GB and this is my primary computer use. Libraries currently live on a 1T Rugged drive and are shared between an 2009 21 iMac and 2010 13MBP. Things are just too slow and I want more screen space. Trying to sort out best use of funds...so, base config looks like this so far:
3.2GHz Quad-core Intel Core i5
16GB 1600MHz DDR3 SDRAM
1TB Fusion Drive
GTX 675MX 1GB GDDR5
In terms of more bang for the buck, does it make sense to upgrade to:
3.4 i7 ($200)
3T Fusion ($150)
680MX 2G ($150)
I currently have a 2T USB 3 external and a 3T Firewire external (Time Machine BU). I am thinking, given I need a mobile solution for traveling and working out of home, keeping the libraries on an external would negate the need to upgrade to a 3T fusion. My understadning of Thunderbolt and USB3 is I would not notice the difference working externally or on an internal Fusion-is this more or less correct? Better to spend the money on an external Thunderbolt when they come down a little more?
680MX is considered a fast gaming card...but might it also "future-proof" (if you can even do that these days!) the mac for graphics requirements to come? Or is it overkill for Aperture and PS? Again-better to spend the money elsewhere?
I am leaning towards the faster processor. Although I hear mixed things, the tests I have seen do say this will give an overall boost.
I would welcome any insights from others who walked this path...
many thanks
NJ