Might be a problem was depending the flat owner, what your electrical box is like, and where power comes in to the house (mini-split usually will have its own dedicated breaker installed). Since its your parents' house and the breaker box won't be filled to capacity already, there's probably no consideration other than money. Noise level wise if you can go for a mini-split it's going to be the quietest and cool the best of all possible options. Costs where you live sound alot more reasonable than here for the install-job. If you can get it that low, then it's definitely worth it to go for a mini-split. ^ I'd go for the mini-split considering you plan to be there for many years more. -Out here I'm using PAC's to cool my computer rooms, yet I'm trying to be economical and not permanent installation. Another good use for PAC's is that they're mobile, if you ever have central air break, or any smaller unit break, you can roll in a PAC and use it temporary rather than having the room cook for a few days. InfiniBand is another option to Ethernet -- check out this blog post. It can be cheaper ... but configuration is also not as straight forward as Ethernet. You don't just plug it in and it works. Sometimes modern motherboards come with 10gbit Ethernet integrated, though these are at the more expensive models. I'd say that the only tradeoff is cost since you'd wind up having to buy extra hardware minimally for the computers you're using right now to get them on a faster network. Only the motherboard influences it, yep. You don't need to be that careful with the brand of ECC memory that you buy beyond just the unbuffered or buffered choices usually. EDIT: I take that back, just don't buy "BlackDiamond" memory per motherboard compatibility. Crucial, Samsung, Kingston, etc, are fine (any big well known brand name). ---Board makers usually post a QVL (qualified vendor list) in their documentation, though I've only had memory that's not on a QVL not-work with BlackDiamond.