Not sure whatthehell you are mining cause this link says otherwise, 1 gtx 1080 ti gives $1.80 net per day on Signatum(SIGT) which is on top on the profit list. So in turn if you paid $700 then your roi will be 433 days and that is assuming you make the same as whattomine says which is not true, expect 20% less than whattomine says and not counting problems, downtime and many other things, meaning your roi will likely be 500 days.

https://whattomine.com/coins?utf8=%E2%9C%93&adapt_q_280x=0&adapt_q_380=0&adapt_q_fury=0&adapt_q_470=1&adapt_q_480=1&adapt_q_570=0&adapt_q_580=0&adapt_q_750Ti=0&adapt_q_10606=0&adapt_q_1070=1&adapt_q_1080=0&adapt_q_1080Ti=1&adapt_1080Ti=trueð=true&factor%5Beth_hr%5D=35.0&factor%5Beth_p%5D=140.0&grof=true&factor%5Bgro_hr%5D=58.0&factor%5Bgro_p%5D=210.0&x11gf=true&factor%5Bx11g_hr%5D=19.5&factor%5Bx11g_p%5D=170.0&cn=true&factor%5Bcn_hr%5D=830.0&factor%5Bcn_p%5D=140.0&eq=true&factor%5Beq_hr%5D=635.0&factor%5Beq_p%5D=190.0&lre=true&factor%5Blrev2_hr%5D=64000.0&factor%5Blrev2_p%5D=190.0&ns=true&factor%5Bns_hr%5D=1400.0&factor%5Bns_p%5D=190.0&lbry=true&factor%5Blbry_hr%5D=460.0&factor%5Blbry_p%5D=190.0&bk2bf=true&factor%5Bbk2b_hr%5D=2800.0&factor%5Bbk2b_p%5D=190.0&bk14=true&factor%5Bbk14_hr%5D=4350.0&factor%5Bbk14_p%5D=210.0&pas=true&factor%5Bpas_hr%5D=1700.0&factor%5Bpas_p%5D=210.0&skh=true&factor%5Bskh_hr%5D=47.5&factor%5Bskh_p%5D=190.0&factor%5Bl2z_hr%5D=420.0&factor%5Bl2z_p%5D=300.0&factor%5Bcost%5D=0.19&sort=Profitability24&volume=0&revenue=24h&factor%5Bexchanges%5D%5B%5D=&factor%5Bexchanges%5D%5B%5D=bittrex&factor%5Bexchanges%5D%5B%5D=bleutrade&factor%5Bexchanges%5D%5B%5D=bter&factor%5Bexchanges%5D%5B%5D=c_cex&factor%5Bexchanges%5D%5B%5D=cryptopia&factor%5Bexchanges%5D%5B%5D=poloniex&factor%5Bexchanges%5D%5B%5D=yobit&dataset=Main&commit=Calculate