Xugo

No problem! This is your motherboard, right? Between the two options, I think it would be best to go with the one 1070 if you're concerned purely with game performance since it doesn't seem like your motherboard supports SLI. But maybe others can chime in. Zero personal experience using multiple GPUs so wouldn't be able to tell you how noticeable the change in performance would be.

Without getting into the technical details, PCI is essentially a type of slot/slot standard. PCI-E is an improved version. Within PCI-E there yet further different versions, with the newer ones typically allowing for better performance. For your GPU to work at full capacity, or sometimes at all, it needs to fit and be compatible with the slots your motherboard has. Your GPU should tell you what types of slot it needs, and your motherboard should tell you what types of slots it has. If all else fails, throw your build into pcpartpicker.com and it should tell you whether or not everything is compatible. Have you heard of the site called slickdeals? If you aren't in a total rush I would recommend creating an alert for that GPU, along with the 1060's and 1080's. Just two weeks ago the community found 1080s for that price on ebay (brand new), but the offer is expired now. But in general new reasonably priced GPUs may be hard to obtain at the moment with the whole cryptocurrency craze... New model releases, as BliitzTheFox mentioned, may help. For the reason stated above, I would be wary of buying used GPUs. The ones used for mining cryptocurrency will have significantly more wear than those with normal use.

As an aside for others considering an upgrade and need to budget, this was mentioned by DU's Facebook page. Reference: https://www.facebook.com/dualuniverse/posts/759311217574586?comment_id=759317544240620

Hm, I guess mine will be the shortest thus far... Minecraft. Most of my gaming growing up was with anime/fantasy MMORPGs. Tried a large variety over time, but mainly stuck with a couple, i.e. Maple Story and Dream of Mirror Online (anyone?). Haven't played anything much ever since the latter stopped being supported by the original publisher. Hoping to get back into gaming with Dual Universe and that it'll be the third MMO I stick with for several years.