There’s no getting away from it, Omnisphere is MASSIVE. In just about every way possible. Aside from the obvious numbers: 6 DVDs, 50gb install, the sounds it produces are simply fist-in-the-face astonishing. From burning pianos to ethereal, naturally-sourced choirs, they will take your breath away, regardless of how well you can play; just hold middle C on pretty much any patch and your ears are filled with lashings of top end synthesis.

Spectrasonics Omnisphere - bigger than yo' mamma
This comes at a price, of course, which is that Omnisphere is rather partial to a slice of CPU… or two. Before getting the synth, I read many reports of it being ‘unuseable’ on anything less that weapon-grade Mac Pro hardware.
As usual, I ignored this advice and went for it. My studio is centred around a dual 1.8ghz PowerPC G5 with 4GB of RAM. Once anounced as the ‘most powerful computer on the planet’, this is now somewhat of a dinosaur, it’s lack of a (or several) multi core Intel CPU pushing it firmly back into Apple’s history books.
So, you’d perhaps expect it to literally explode when Omnisphere is loaded up in Logic. Not so. It loads up in a matter of seconds and pretty much every patch can be played through without fuss. So, don’t believe what you read in Blogs…
The problems start to manifest themselves when you attempt to use it for real in a project. Aside from the obvious problem of finding a track willing enough to allow the somewhat obese aural qualities of the synth to sit alongside other instruments without drowning them out, if you go for any more than two instances, and your Mac is similarly spec’d to mine, you’ll run into the eternally frustrating ‘can’t process audio’ error.
To get round this, I recommend something which is actually quite obvious, but may not come instantly to mind. Record your Omnisphere part and then bounce it to audio. Once bounced, create an audio track, plonk the audio file into it and remove the soft synth Omnisphere track. Hey presto – your CPU can breath a sigh of relief and you can still garnish your tracks with noises God makes when he’s rearranging furniture. Just remember to leave a gap at the end of your bounce for any reverb or delay which might tail off.
I recently put together this track which is an example of this monolith in action. It’s also worth noting that of the three Omnispheres used in this piece, two of them are real instances, not audio and it didn’t cause Logic any trouble (although it was right on the edge at times).