Considering an IMac 2014 4.0Ghz model.

[Straight2Vinyl]

Hey guys. So after saving to get a Roli Seaboard, my PC gave me the blank screen treatment last night. lol. I was going to wait another year to replace it, but the time may be now if I can't fix it. I've been on the fence about getting a new PC again(with 8700K cpu) or an IMac. The IMac price is a little off putting though.
Today I came across a used late 2014 model IMac with 4.0Ghz quad core processor, 16gb ram and 512ssd.
The price is quite reasonable based on the spec I think(1999 Canadian). I looked up single core processors and while this is an older model, it's still ranked 11th in top processor speeds. I'm wondering is there any down side here from a music production standpoint? I haven't played video games in years, so that's not a factor at all. The 5K retina screen seems nice to have, as I've watched video on my girlfriends 5K MacBook before.

I mainly want to get more use out of my most demanding plugins, which are mainly Reaktor and Iris 2(both single core only), so I think the 4Ghz could be a winner. My old PC is a quad core AMD 2.7ghz, so it looks like a huge jump in polyphony.
I don't mind that it has the older Thunderbolt 2 interface as the fastest tested interface to date, that I'm aware of, was the Quantum which was TB 2 anyway. I'll be getting a 4 in 4 out Behringer though most likely for now though.
The biggest weakness of the system appears to be that it is DDR3 ram, but I don't know how much that will effect me doing music production.
Is there anything I'm really going to miss out on by getting this machine as opposed to a newer Mac or brand new PC? Again, I'm not at all concerned with video game performance. I may pick up Final Cut Pro some day for video editing, but that's not my main concern. I just want to know if this will be able to handle approx.

[Tj Shredder]

The big 5 k is extensible in terms of RAM (important if it would have too little...) The newer models are faster, but less easy to repair/maintain...
It sounds good though if the price is reasonable...