Aside from the whole software for rent issue (which I also personally disagree with for the same reasons - stop paying and you cannot use your files, period, with a normal license you can run it forever if you want) I believe Flexi, which we also use if mostly dependent on processor speed. That being said I'm also Intel partial - an over a year older i7-3770 easily outperforms the over a year newer A8-6600K... The A8 you have is no slouch though and will serve Flexi just fine.
We also separate the RIP (Production Manager) from the design end (Flexi Design). As far as the Design end it really depends on what you are doing in it. I don't think Flexi is a native 64 bit program (it is fully supported and works great on x64 Windows) but notice that it installs to Program Files (x86) instead of Program Files (which is strictly for native x64 applications). As such I'm not sure Flexi can really even address the ram in the system beyond 4GB. I do know that it benefits greatly from very fast disk access when it comes to opening and saving large files but a 120gb SSD is dismally small for holding much in the way of client files and almost unusable for the Production Manager (RIP) end as the RIP end will fill up a 120GB SSD in very very short order unless you are constantly deleting everything out of Production Manager. Realistically though, as far as the design end I'm not really sure how much processor and ram will affect it since we personally do not "design" in Flexi other than maybe quickie type layouts for cheap coro signs. We really just bring designs into it to add contour cuts, nest, and send them to Production Manager, we do the design work in Adobe programs. In the end I'd say give it a go with the hardware you have. Its a very capable system. Let the new guy bang on it for a bit and see how it goes, if he is complaining about speed throw some money at the machine.
