Hi guys, my old 24'' core2 extreme imac is getting really old and slow. So I'm thinking to change it with a new one. Note that I actually have a 13'' rMBP i7. I use my 24'' as an always on machine, able to rip dvd/cd heavily downloads and so on. I've seen that there are some 21.5'' iMac in refurbished, but I only see machines with a 5400 rpm disk (the standard) and a 27'' iMac in refurbished with a 7200 rpm disk. No fusion/ssd machines there, unless I allow an i5 processor. Generally the 21 and 27 have 8 Gb RAM. Should I prefer an i5 with a fusion drive or an i7 with a normal drive (5400 seems odd to me, and the possibility to replace the drive seems difficult too, according to ifixit)? Or should I consider a new and totally configured machine?