Hi Tony,
Since I heard you were getting a new PC I did a bit of "Googling" on the use of SSD's. It does seem that SSD's do a have lifespan dependant on the number of writes. It will also depend on how much spare space there is on the SSD, more the better to minimise the density of writes.
I suggest you Google SSD lifespan but I found these items yesterday:
http://www.tomshardware.com/reviews/ssd-upgrade-hard-drive,2956.html
http://maxschireson.com/2011/04/21/debunking-ssd-lifespan-and-random-write-performance-concerns/
Bear in mind that the QU thumbnail and raw cache will always be on the SSD (Application data) and needs managing from time to time. QU has a utility to do this.

You are right, migration is to move the program application data to another directory or drive.
QU has a great facility called "Flash card Copy/Move" (FCCM) to do exactly what you require. I suggest the following:
Use FCCM to copy new images from your card to the SSD, Internal HDD and external HDD (as backup). Re-name with FCCM as they are copied as required. See 1st screen shot below which shows to C-drive and an external drive.
The folder structure on all 3 drives should set up to be the same.

When you are ready to clear the SSD and update internal & external HDD use FCCM to do it in Update mode.
See the 2nd screen shot where I have browsed to the SOURCE folder; the sub folders also get recognised & copied
My next post has the remaining screen shots for the rest of the process.
Terry

Thanks Terry,

I've got about an hour 'play time' before I need to go out.

I'll experiment with your suggestions and also do some timing to see if the SSD is quicker when it also holds the images.

Tony

Creating thumbs and cache is processor dependant rather than on memory write speed.
My PC shop installed a utility to boost my speed, see screen shot below. I went from 3.1GHz to 3.5Ghz but I do monitor processor temperatures too with a desktop widget. Video processing is far more demanding that QU.
My speed tests did show a useful improvement in cache times. When I got my new 18Mpix 600D, the time difference was noticeable compared to the 8Mpix 350D but I soon got used to it. I wouldn't want to do raw in any other way; other programs seems to have their own disadvantages.
Have you tried off-loading a memory card to the different drives to see if there's a significant difference?
Terry
PS. now added screen shot.

I think that's wise; my PC builder installed the utility after the PC was almost a year old while they were checking, funnily enough, hard drive transfer rates. They upgraded to BIO too.
Did you use QU Flash card copy/Move/ That is as fast as you'll get? It seems to have a better "engine" than the standard Windows copy/move.
Terry