GTX 1080 Asus strix x4 ? Sol/s hashrate

Hello Guys,
I made a rig with
ASUS 270P mother board
8gb ram
2tb seagate HDD
4x Asus GTX 1080 Strix
Now i am not over clocking system. I only use Asus performance tool. tool has silent gaming and overclock mode. I preferred overclock mode. mining with EWBF cuda miner tool. in nanopool i am mining and it is giving max 2000 sol/s. also i am checking hashrate probability from https://www.cryptocompare.com/mining/calculator/zec?HashingPower=1900&HashingUnit=H%2Fs&PowerConsumption=1200&CostPerkWh=0 it is showing 200usd per month but tool from nanopool shows i can get 180 usd per month do i make something wrong?

The link from Cryptocompare shows you the optimal (best case) mining return.

NanoPool is showing you, based on the pools luck, what your likely average should be.

so the best scenario is the cryptocompare but most true one is nanopools guess, by the way do you advice any other pool or nanopool is good? or solo mining can be applicable for my system?

Yes.

unless you have a minimum of 200k H/s rate, I would not solo mine, and you probably need 500k

Nanopool, flypool, suprnova, and I know I am forgetting someone are the top 3 or 4 pools

I switched from suprnova to flypool and have been happy and mining there for two months. And also i would recommend manually overclocking with for example MSI Afterburner. My Asus Strix 1070 with Samsung memory gets 500sols/s when at 100% power and 460sols at 80% (+100 core and +800 memory. voltage unchanged). So you should get a little more then 500 per card.