"First of all, Do this at your own RISK" I do not hold any liability/responsibiluty to what ever happens to your system. But I assure you this method is safe.
After Summerset patch, everyone was experiencing severe performance issues. Some of the low end rigs suffered a lot, some also improved a lot.
This is a short guide for low end pc's and laptops only. also tested this on my friend's lower specd pc and worked like a charm. I am testing this on my laptop.
As for my pc im still currently having fps drops from time to time. Anyway lets get this over with.

PROS: Super duper fps increase in Overworld, Dungeons, BG 60-90, but not too much in cyrodiil during siege. Still drops 20-50fps. I just don't know why.
CONS: looks like a game from 2006, Everythng looks quite dry.
But if you prefer gameplay performance over the beautiful world? hurray!

Before I applied this settings I was getting around 10-30fps in towns, 20-50 overworld, etc.

Laptop specs:
Win10
i7 4510U 2.6Ghz
4gb dd3 ram (THE GREATEST BOTTLENECK)
GeForce 840m
No SSD

Always start with the BASICS. Before we get to the Game Settings
(Use google if you don't know where to navigate)
-Defrag your drive(s)
-Set your power plan to "High Performance"
Optional: Virus scan
Optional: Disable unecessary Startup bloatware or unused apps or programs in task manager or msconfig(if not win10)
Optional:Delete everything on your %temp% folder (do not force delete files that does not delete, just skip it).

IMPORTANT *do this first, You can also backup your own copy and rename it to morriwndsettings etc. for remembrance purposes.*
Delete your UserSettings found on (\Documents\Elder Scrolls Online\live)
Run your game and let it rebuild a new one. (you might have a longer loadscreen for awhile)

In Game settings
This is my current settings.
Display
Display Mode: Fullscreen
Resolution: (Use your native Resolution)
Vertical sync:Off
Anti-aliasing: Off
Graphics
Graphics Quality: (this will change to custom, because later, yep)
Texture Quality: High (Adjust this if it improves more fps for you)
Subsampling Quality:High (Adjust this if it improves more fps for you)
Shadow Quality:Low
Water Reflection Quality:Off
Maximum particle Systems: 768(Drag the bar to Lowest)
Particle Suppression Distance:35(Drag the bar to Lowest)
View Distance: (up to you)
Ambient Occlusion: Off
Bloom: Off
Depth of Field: Off
Distortion: Off
Sunlight Rays: Off
Grass:Off
Show additional Ally Effects. Off

Now Close your game and navigate to (\Documents\Elder Scrolls Online\live)
Open the NEW UserSettings (if it prompts to ask open with, Open it with notepad)
Make sure to save a backup before overwriting the NEW file. To ensure a simple revert.
Now look for these key settings and change their variables to "0" (some might already been set to 0)

SET CachedReflectionResolution "0"
SET CachedShadowFiltering "0"
SET REFLECTION_QUALITY_v3 "0"
SET PARTICLE_DENSITY "0"
SET HIGH_RESOLUTION_SHADOWS "0"
SET SHADOWS "0"
SET GPUSmoothingFrames "0"
SET MIP_LOAD_SKIP_LEVELS "0"
SET RAIN_WETNESS "0"
SET LENS_FLARE "0"
SET GOD_RAYS_v2 "0"
SET ANTI_ALIASING_v2 "0"
SET AMBIENT_OCCLUSION "0"
SET TONE_MAPPING "0"
SET SOFT_ALPHA "0"
SET NORMAL_MAPS "0"
SET SPECULAR_MAPS "0"
SET SIMPLE_SHADERS "1" (yes 1, you can test this and check if this gives you better fps. it did for me)
SET WATER_FOAM "0"
SET VSYNC_INTERVAL "0"
SET VSYNC "0"
SET MAX_ANISOTROPY "0"
SET FullscreenHeight "x" (Be sure to check this, it should be your native resolution)
SET FullscreenWidth "x" (Be sure to check this, it should be your native resolution)
SET MaxCoresToUse.4 "-1" (-1 means unlimited, pls correct me if im wrong. means it uses all, you can change this if you want, up to you)
SET RequestedNumJobThreads "0"
SET RequestedNumWorkerThreads "0"

HIT SAVE

Now after all this, give your pc a nice restart.. and enjoy the game.. I hope this helps. If you guys can share more details please and please put it down below.

Im Really Curious about this.
SET FreeUnusedGrannyFileSections.2 "0"

But there's this