May i ask if all gtx 1080ti are same hashrate speed.. i mean there are different manufacturer and different specs .. Let me know if there is a big differences of hashrate speed when mining ethereum or what altcoin is much profitable these days..
no, in fact they are not, while some of them are close enough
if you want highest possible hashrate yet to have very low noise level and temperatures then choose one from these
asus OC stryx
zotac amp extreme
gigabyte Aourus extreme
msi lighting
evga Ti FTW3 DT
and some hybrid models ( though they usually more expensive)
take any of these and you would be just fine!