diff --git a/api/api.lua b/api/api.lua
index 0405b00d..e2850c1a 100644
--- a/api/api.lua
+++ b/api/api.lua
@@ -992,28 +992,53 @@ function pfUI.api.GetBorderSize(pref)
   end
 end
 
+-- The scale UIParent ends up with: one UI unit per screen pixel when pixel
+-- perfect, else the game's own. The game applies its scale only after the
+-- add-ons and their saved variables are loaded (CGGameUI::Initialize ends in
+-- OnDisplaySizeChanged), so at load time it is worked out from the same
+-- options and rules: uiScale while useUiScale is on and it is at least 0.64,
+-- else 768 over the window height kept within 0.9 and 1. Windows narrower
+-- than 4:3 cap either at 3/4 of their aspect.
+local function GetUIScale()
+  if pfUI_config.global.pixelperfect == "1" then return PixelUtil.GetPixelToUIUnitFactor() end
+
+  local width, height = GetPhysicalScreenSize()
+  local aspect = GetCVar("widescreen") == "1" and width / height or 4/3
+  local function fit(scale)
+    return aspect < 4/3 and math.min(scale, aspect * .75) or scale
+  end
+
+  if GetCVar("useUiScale") == "1" then
+    local scale = fit(tonumber(GetCVar("uiScale")))
+    if scale >= .64 then return scale end
+  end
+
+  return math.max(fit(height > 768 and 768 / height or 1), .9)
+end
+
+-- [ UpdateUIScale ]
+-- Gives UIParent the pixel perfect scale when enabled, else leaves the game's
+-- own. The engine puts its own scale back on every window resize and scale
+-- option change, so this runs again on each UI_SCALE_CHANGED. Borders keep
+-- the pixel size they were built with, so a change of it offers a reload once.
+function pfUI.api.UpdateUIScale()
+  if pfUI_config.global.pixelperfect == "1" then
+    UIParent:SetScale(PixelUtil.GetPixelToUIUnitFactor())
+  end
+
+  if not pfUI.pixel or pfUI.scaleprompt then return end
+  if math.abs(PixelUtil.GetPixelToUIUnitFactor() / UIParent:GetScale() - pfUI.pixel) < .0001 then return end
+
+  pfUI.scaleprompt = true
+  CreateQuestionDialog(T["The UI-Scale has changed. Reload the UI to redraw the borders?"], ReloadUI)
+end
+
 -- [ GetPerfectPixel ]
--- Returns a number that equals a real pixel on regular scaled frames.
--- Respects the current UI-scale and calculates a real pixel based on
--- the screen resolution and the 768px sized drawlayer.
+-- Returns the size of one physical pixel in UIParent units.
 function pfUI.api.GetPerfectPixel()
   if pfUI.pixel then return pfUI.pixel end
 
-  if pfUI_config.appearance.border.pixelperfect == "1" then
-    local scale = GetCVar("useUiScale") == "1" and GetCVar("uiScale") or "1"
-    local resolution = GetCVar("gxResolution")
-    local _, _, screenwidth, screenheight = strfind(resolution, "(.+)x(.+)")
-
-    pfUI.pixel = 768 / screenheight / scale
-    pfUI.pixel = pfUI.pixel > 1 and 1 or pfUI.pixel
-
-    -- autodetect and zoom for HiDPI displays
-    if pfUI_config.appearance.border.hidpi == "1" then
-      pfUI.pixel = pfUI.pixel < .5 and pfUI.pixel * 2 or pfUI.pixel
-    end
-  else
-    pfUI.pixel = .7
-  end
+  pfUI.pixel = PixelUtil.GetPixelToUIUnitFactor() / GetUIScale()
 
   pfUI.backdrop = {
     bgFile = "Interface\\BUTTONS\\WHITE8X8", tile = false, tileSize = 0,
diff --git a/api/config.lua b/api/config.lua
index 8987796c..5ee3ead3 100644
--- a/api/config.lua
+++ b/api/config.lua
@@ -129,9 +129,7 @@ function pfUI:LoadConfig()
   pfUI:UpdateConfig("appearance", "border",      "color",            "0.2,0.2,0.2,1")
   pfUI:UpdateConfig("appearance", "border",      "shadow",           "0")
   pfUI:UpdateConfig("appearance", "border",      "shadow_intensity", ".35")
-  pfUI:UpdateConfig("appearance", "border",      "pixelperfect",     "1")
   pfUI:UpdateConfig("appearance", "border",      "force_blizz",      "0")
-  pfUI:UpdateConfig("appearance", "border",      "hidpi",            "1")
   pfUI:UpdateConfig("appearance", "border",      "default",          "3")
   pfUI:UpdateConfig("appearance", "border",      "nameplates",       "-1")
   pfUI:UpdateConfig("appearance", "border",      "actionbars",       "-1")
diff --git a/init/modules.xml b/init/modules.xml
index febafbdc..bfb2ece6 100644
--- a/init/modules.xml
+++ b/init/modules.xml
@@ -54,7 +54,6 @@
   <Include file="..\modules\gm.lua"/>
   <Include file="..\modules\mirrortimers.lua"/>
   <Include file="..\modules\feigndeath.lua"/>
-  <Include file="..\modules\pixelperfect.lua"/>
   <Include file="..\modules\hdgraphic.lua"/>
   <Include file="..\modules\share.lua"/>
   <Include file="..\modules\tracking.lua"/>
diff --git a/modules/firstrun.lua b/modules/firstrun.lua
index 072d408e..1f5c46e2 100644
--- a/modules/firstrun.lua
+++ b/modules/firstrun.lua
@@ -136,17 +136,19 @@ pfUI:RegisterModule("firstrun", function ()
     local f = CreateFirstRunPage()
     f.text:SetText(T["A new installation of |cff33ffccpf|rUI ships with 4 prebuilt design profiles. Click below if you wish to load one of these profiles."])
 
+    local function LoadProfile(name)
+      _G["pfUI_config"] = CopyTable(pfUI_profiles[name])
+      pfUI_init.selected_profile = name
+      pfUI:LoadConfig()
+      ReloadUI()
+    end
+
     f.Modern = CreateFrame("Button", nil, f, "UIPanelButtonTemplate")
     f.Modern:SetSize(120, 20)
     f.Modern:SetPoint("BOTTOM", -65, 100)
     f.Modern:SetTextColor(1,1,1)
     f.Modern:SetText("Modern")
-    f.Modern:SetScript("OnClick", function()
-      _G["pfUI_config"] = CopyTable(pfUI_profiles["Modern"])
-      pfUI_init.selected_profile = "Modern"
-      pfUI:LoadConfig()
-      ReloadUI()
-    end)
+    f.Modern:SetScript("OnClick", function() LoadProfile("Modern") end)
     SkinButton(f.Modern)
 
     f.Nostalgia = CreateFrame("Button", nil, f, "UIPanelButtonTemplate")
@@ -154,12 +156,7 @@ pfUI:RegisterModule("firstrun", function ()
     f.Nostalgia:SetPoint("BOTTOM", 65, 100)
     f.Nostalgia:SetTextColor(1,1,1)
     f.Nostalgia:SetText("Nostalgia")
-    f.Nostalgia:SetScript("OnClick", function()
-      _G["pfUI_config"] = CopyTable(pfUI_profiles["Nostalgia"])
-      pfUI_init.selected_profile = "Nostalgia"
-      pfUI:LoadConfig()
-      ReloadUI()
-    end)
+    f.Nostalgia:SetScript("OnClick", function() LoadProfile("Nostalgia") end)
     SkinButton(f.Nostalgia)
 
     f.Legacy = CreateFrame("Button", nil, f, "UIPanelButtonTemplate")
@@ -167,12 +164,7 @@ pfUI:RegisterModule("firstrun", function ()
     f.Legacy:SetPoint("BOTTOM", 65, 75)
     f.Legacy:SetTextColor(1,1,1)
     f.Legacy:SetText("Legacy")
-    f.Legacy:SetScript("OnClick", function()
-      _G["pfUI_config"] = CopyTable(pfUI_profiles["Legacy"])
-      pfUI_init.selected_profile = "Legacy"
-      pfUI:LoadConfig()
-      ReloadUI()
-    end)
+    f.Legacy:SetScript("OnClick", function() LoadProfile("Legacy") end)
     SkinButton(f.Legacy)
 
     f.Slim = CreateFrame("Button", nil, f, "UIPanelButtonTemplate")
@@ -180,12 +172,7 @@ pfUI:RegisterModule("firstrun", function ()
     f.Slim:SetPoint("BOTTOM", -65, 75)
     f.Slim:SetTextColor(1,1,1)
     f.Slim:SetText("Slim")
-    f.Slim:SetScript("OnClick", function()
-      _G["pfUI_config"] = CopyTable(pfUI_profiles["Slim"])
-      pfUI_init.selected_profile = "Slim"
-      pfUI:LoadConfig()
-      ReloadUI()
-    end)
+    f.Slim:SetScript("OnClick", function() LoadProfile("Slim") end)
     SkinButton(f.Slim)
 
     f.Slider = CreateFrame("Slider", "pfFirstRunWizardScaleSlider", f, "OptionsSliderTemplate")
@@ -196,14 +183,14 @@ pfUI:RegisterModule("firstrun", function ()
     f.Slider:SetSize(240, 20)
     f.Slider:SetPoint("BOTTOM", 0, 50)
     f.Slider:SetOrientation('HORIZONTAL')
-    f.Slider:SetMinMaxValues(0.5, 2.0)
+    -- the game drops a uiScale under 0.64 for its automatic scale at login
+    f.Slider:SetMinMaxValues(0.64, 2.0)
     f.Slider:SetValue(UIParent:GetScale())
 
     f.Slider:SetScript("OnMouseUp", function()
       local scale = round(this:GetValue(),2)
       SetCVar("uiScale", scale)
       SetCVar("useUiScale", 1)
-      UIParent:SetScale(scale)
       this:SetValue(scale)
     end)
 
diff --git a/modules/gui.lua b/modules/gui.lua
index 77a325b7..03397952 100644
--- a/modules/gui.lua
+++ b/modules/gui.lua
@@ -130,7 +130,7 @@ pfUI:RegisterModule("gui", function ()
         category = {}
         category[config] = tostring(GetCVar(config))
         ufunc = function()
-          SetCVar(this:GetParent().config, this:GetParent().category[config])
+          SetCVar(config, category[config])
         end
       end
 
@@ -881,14 +881,6 @@ pfUI:RegisterModule("gui", function ()
         "35:35",
         "40:40",
       },
-      ["scaling"] = {
-        "0:" .. T["Off"],
-        "4:" .. T["Huge (PixelPerfect)"],
-        "5:" .. T["Large"],
-        "6:" .. T["Medium"],
-        "7:" .. T["Small"],
-        "8:" .. T["Tiny (PixelPerfect)"],
-      },
       ["abbrevnum"] = {
         "0:" .. T["Full Numbers (4250)"],
         "1:" .. T["Abbreviate 2 Decimals (4.25k)"],
@@ -1508,7 +1500,24 @@ pfUI:RegisterModule("gui", function ()
 
       CreateConfig(nil, T["Settings"], nil, nil, "header")
       CreateConfig(nil, T["Language"], C.global, "language", "dropdown", pfUI.gui.dropdowns.languages)
-      CreateConfig(U["pixelperfect"], T["Enable UI-Scale"], C.global, "pixelperfect", "dropdown", pfUI.gui.dropdowns.scaling)
+      -- the game's own scale options, as in its Video Options; the list keeps
+      -- a value set there that is none of these steps
+      CreateConfig(nil, T["Use UI-Scale"], "CVAR", "useUiScale", "checkbox")
+      CreateConfig(nil, T["UI-Scale"], "CVAR", "uiScale", "dropdown", function()
+        local current = GetCVar("uiScale")
+        local values, found = {}, nil
+        for _, scale in ipairs({ .64, .65, .7, .75, .8, .85, .9, .95, 1, 1.1, 1.2, 1.3, 1.4, 1.5 }) do
+          if math.abs(scale - tonumber(current)) < .001 then
+            found = true
+            table.insert(values, current .. ":" .. scale)
+          else
+            table.insert(values, tostring(scale))
+          end
+        end
+        if not found then table.insert(values, 1, current .. ":" .. round(tonumber(current), 2)) end
+        return values
+      end)
+      CreateConfig(nil, string.format(T["Pixel Perfect UI-Scale: %s (Overrides UI-Scale)"], round(PixelUtil.GetPixelToUIUnitFactor(), 2)), C.global, "pixelperfect", "checkbox")
       CreateConfig(nil, T["Use Original Game Fonts"], C.global, "font_blizzard", "checkbox")
       CreateConfig(nil, T["Enable Region Compatible Font"], C.global, "force_region", "checkbox")
       CreateConfig(nil, T["Standard Text Font"], C.global, "font_default", "dropdown", pfUI.gui.dropdowns.fonts)
@@ -1585,8 +1594,6 @@ pfUI:RegisterModule("gui", function ()
       CreateConfig(nil, T["Frame Shadow Intensity"], C.appearance.border, "shadow_intensity", "dropdown", pfUI.gui.dropdowns.uf_debuff_indicator_size)
       CreateConfig(nil) -- spacer
       CreateConfig(nil, T["Force Blizzard Borders (|cffffaaaaExperimental|r)"], C.appearance.border, "force_blizz", "checkbox")
-      CreateConfig(nil, T["Enable Pixel Perfect Borders"], C.appearance.border, "pixelperfect", "checkbox")
-      CreateConfig(nil, T["Scale Border On HiDPI Displays"], C.appearance.border, "hidpi", "checkbox")
       CreateConfig(nil) -- spacer
       CreateConfig(nil, T["Global Border Size"], C.appearance.border, "default", "dropdown", pfUI.gui.dropdowns.border)
       CreateConfig(nil, T["Action Bar Border Size"], C.appearance.border, "actionbars", "dropdown", pfUI.gui.dropdowns.border)
diff --git a/modules/pixelperfect.lua b/modules/pixelperfect.lua
deleted file mode 100644
index 872b5d37..00000000
--- a/modules/pixelperfect.lua
+++ /dev/null
@@ -1,43 +0,0 @@
-pfUI:RegisterModule("pixelperfect", function ()
-  -- pre-calculated min values
-  local statics = {
-    [4] = 1.4222222222222,
-    [5] = 1.1377777777778,
-    [6] = 0.94814814814815,
-    [7] = 0.81269841269841,
-    [8] = 0.71111111111111,
-  }
-
-  -- pixel perfect
-  local function pixelperfect()
-    local conf = tonumber(C.global.pixelperfect)
-    if conf < 4 then
-      -- restore gamesettings
-      local scale = GetCVar("uiScale")
-      local use = GetCVar("useUiScale")
-
-      if use == 1 then
-        UIParent:SetScale(tonumber(use))
-      else
-        UIParent:SetScale(.9)
-      end
-    else
-      local scale = conf and statics[conf] or 1
-
-      SetCVar("uiScale", scale)
-      SetCVar("useUiScale", 1)
-
-      UIParent:SetScale(scale)
-    end
-  end
-
-  -- pixelperfect: native UIScale listener
-  if tonumber(C.global.pixelperfect) > 0 then
-    pfUI.events:RegisterFrameEventAndCallback("PLAYER_ENTERING_WORLD", pixelperfect)
-    pixelperfect()
-  end
-
-  pfUI.pixelperfect = {
-    UpdateConfig = pixelperfect
-  }
-end)
diff --git a/pfUI.lua b/pfUI.lua
index 6b1fe21d..ea9d3d0d 100644
--- a/pfUI.lua
+++ b/pfUI.lua
@@ -392,6 +392,10 @@ pfUI:SetScript("OnEvent", function()
     SetupConfigEnvironment()
     pfUI:UpdateFonts()
 
+    -- scale UIParent before the modules size their borders from it
+    pfUI.api.UpdateUIScale()
+    pfUI.events:RegisterFrameEventAndCallback("UI_SCALE_CHANGED", pfUI.api.UpdateUIScale)
+
     -- load modules
     for _, m in pairs(this.modules) do
       if not ( pfUI_config["disabled"] and pfUI_config["disabled"][m]  == "1" ) then