I upgraded from Sierra to High Sierra tonight. Updated to the latest web drivers and the lag made my hack unusable.
I have been reading and experimenting for the last couple of hours but only downgrading to the .25.106 drivers with the nvidia-update.sh script has seemed to make it acceptable. Command I used was:
bash <(curl -s
https://raw.githubusercontent.com/Benjamin-Dobell/nvidia-update/master/nvidia-update.sh) 378.10.10.10.25.106
Tried latest WhateverGreen + Lilu in the Other folder with the latest drivers and it didn't work for me.
If anyone has any further troubleshooting ideas I am all ears! My system is still a little laggy but it's usable at this stage. Definitely not as responsive as Sierra.
The discussion in this thread has mostly been about two-NVIDIA cards installation and how the recent web drivers, unlike previous ones, will not allow proper usage of the two cards.
The lag issue from previous web drivers has been solved for almost everyone with a recent single NVIDIA card.
My installation, with a Gigabyte Z87 board, the 4770K Haswell CPU, and a 1080 Ti card
like yours, using the latest NVIDIA web driver and CUDA driver--387.10.10.1040.105 and 396.148--runs PERFECTLY, and I mean perfectly. No lag, no problems.
So what is causing your issue with lag? Something with your installation, the web driver, the kexts, or UEFI-64 drivers. You made a big leap from Sierra to High Sierra 10.13.6.
Now, when I went to install the 10.13.6 update I tried to update my Clover installation and made the change to the new drivers--and I know what I'm doing--and something in this mess of changes meant that my boot up would lead to a black screen. I do not have hours to decode the problem through experimentation, so I simply tried my 10.13.5 Clover setup. It worked, of course. What you had from Sierra might well not.
Here are pics of my kexts and UEFI-64 drivers from my clover installation.
I use HFS+, not APFS, because I have a lot of drives and many HDDs. I might convert with Mojave, not now. I put in the apfs.efi from my system just for the hell of it. And I think that's still the best way to do it. I use iMac15,1. (14,2 also good).
Recommendations, since your system and mine are almost the same--and note--please do everything on a CLONE of your drive:
1) Download newest NVIDIA web driver onto your desktop. Uninstall your current older NVIDIA web driver by using the PREFERENCE PANE in system preferences, CUDA too if you have it installed. Reboot. Now install the new web driver, and CUDA if you feel like it. Reboot. How's it working now? The old school rule: Always physically uninstall GPU drivers before you install new ones. If that's not enough:
2) Forget the new UEFI drivers that are primarily for newer chips like 7th and 8th Gen. Forget the newer Clover versions. I use 4509 (get it from Downloads here), and RehabMan's is 4444--and I know for a fact that a user with a Z87 used RehabMan's 4444 to install 10.13.6, with the latest web drivers! Get your kexts from RehabMan's bitbucket where available.
3) Use the kexts and UEFI-64 drivers that I use. I worked this deal out over the whole Sierra-High Sierra period.
4) In order to disable
CSM you must not use "Other OS" in BIOS.
Instead set to "Windows 8" (and if you dual-boot and use Windows 10, that's the setting as well; if your system is macOS only you still set to Windows 8). When you do that it opens up the CSM Support setting below it. Now change that setting to
"Never." See post #53, by Antilogical:
https://www.tonymacx86.com/threads/...high-sierra-black-screen-panics.234390/page-6
Solves a monitor blackout. Now the Clover boot loader and the entire boot up process are in full resolution, and the startup takes less time.
5) The settings in my Clover config.plist are another matter. You may need help there, but try the above for now. You must drop the MATS table for sure if you haven't. Enable Trust in SMBIOS. (You can have SIP engaged now, try it on even as you install the web drivers.) In System Parameters, both Inject System ID and NvidiaWeb checked on, of course. Etc. Whatever you do with SIP keep it consistent, per RehabMan.
No reason why you can't use the latest web drivers perfectly well. Hars, good luck!