diff --git a/ftplugin/markdown.lua b/ftplugin/markdown.lua
index 8d9aed0..05a2846 100644
--- a/ftplugin/markdown.lua
+++ b/ftplugin/markdown.lua
@@ -75,17 +75,33 @@ vim.api.nvim_create_autocmd({ "BufWinEnter" }, {
 
 		markview.state.buf_states[buffer] = true;
 
-		local parsed_content = markview.parser.init(buffer, markview.configuration);
+		local lines = vim.api.nvim_buf_line_count(buffer);
 
 		markview.renderer.clear(buffer);
-		markview.renderer.render(buffer, parsed_content, markview.configuration)
+
+		if lines < (markview.configuration.max_length or 1000) then
+			local parsed_content = markview.parser.init(buffer, markview.configuration);
+
+			markview.renderer.render(buffer, parsed_content, markview.configuration)
+		else
+			local cursor = vim.api.nvim_win_get_cursor(0);
+			local start = math.max(0, cursor[1] - (markview.configuration.render_range or 100));
+			local stop = math.min(lines, cursor[1] + (markview.configuration.render_range or 100));
+
+			local parsed_content = markview.parser.parse_range(buffer, markview.configuration, start, stop);
+
+			markview.renderer.render(buffer, parsed_content, markview.configuration)
+		end
+
+		-- This needs all of the buffer to be parsed
+		local keymap_content = markview.parser.init(buffer, markview.configuration);
 
 		for _, window in ipairs(windows) do
 			if markview.configuration.callbacks and markview.configuration.callbacks.on_enable then
 				pcall(markview.configuration.callbacks.on_enable, buffer, window);
 			end
 
-			markview.keymaps.init(buffer, window, parsed_content, markview.configuration);
+			markview.keymaps.init(buffer, window, keymap_content, markview.configuration);
 		end
 	end
 });
@@ -123,28 +139,45 @@ vim.api.nvim_create_autocmd({ "ModeChanged", "TextChanged" }, {
 
 		::noCallbacks::
 
+		-- Mode is a valid mode
 		if markview.configuration.modes and vim.list_contains(markview.configuration.modes, mode) then
-			local parsed_content = markview.parser.init(buffer, markview.configuration);
-			local parse_start, parse_stop = utils.get_cursor_range(buffer, windows[1]);
+			local lines = vim.api.nvim_buf_line_count(buffer);
+			local parsed_content;
 
 			markview.renderer.clear(buffer);
 
-			local partial_contents = markview.parser.parse_range(event.buf, markview.configuration, parse_start, parse_stop);
-			local current_range = markview.renderer.get_content_range(partial_contents);
+			if lines < (markview.configuration.max_length or 1000) then
+				parsed_content = markview.parser.init(buffer, markview.configuration);
 
-			if markview.configuration.hybrid_modes and vim.list_contains(markview.configuration.hybrid_modes, mode) then
-				markview.renderer.render(buffer, parsed_content, markview.configuration, parse_start, parse_stop);
-				markview.renderer.clear_content_range(event.buf, partial_contents)
-			else
 				markview.renderer.render(buffer, parsed_content, markview.configuration);
-			end
+			else
+				local cursor = vim.api.nvim_win_get_cursor(0);
+				local start = math.max(0, cursor[1] - (markview.configuration.render_range or 100));
+				local stop = math.min(lines, cursor[1] + (markview.configuration.render_range or 100));
 
-			-- Or else things won't render on first redraw from the other autocmd
-			markview.renderer.update_range(buffer, current_range);
+				parsed_content = markview.parser.parse_range(buffer, markview.configuration, start, stop);
+
+				markview.renderer.render(buffer, parsed_content, markview.configuration)
+			end
 
 			for _, window in ipairs(windows) do
 				markview.keymaps.init(buffer, window, parsed_content, markview.configuration);
 			end
+
+			local cursor = vim.api.nvim_win_get_cursor(0);
+			local start = math.max(0, cursor[1] - 1);
+			local stop = math.min(lines, cursor[1]);
+
+			local under_cursor = markview.parser.parse_range(event.buf, markview.configuration, start, stop);
+			local clear_range = markview.renderer.get_content_range(under_cursor);
+
+			if not clear_range or not clear_range[1] or not clear_range[2] then
+				return;
+			end
+
+			markview.renderer.clear(event.buf, clear_range[1], clear_range[2])
+
+		-- Mode is not a valid mode. Clear decorations.
 		else
 			-- Call an extra redraw to flush out screen updates
 			markview.renderer.clear(buffer);
@@ -186,35 +219,47 @@ vim.api.nvim_create_autocmd(events, {
 
 		move_timer:stop();
 		move_timer:start(100, 0, vim.schedule_wrap(function ()
-			if not _G.__markview_render_ranges then
-				_G.__markview_render_ranges = {};
-			end
+			local lines = vim.api.nvim_buf_line_count(event.buf);
+			local buffer = event.buf;
 
-			if not _G.__markview_render_ranges[event.buf] then
-				_G.__markview_render_ranges[event.buf] = {};
+			local parsed_content;
+
+			markview.renderer.clear(buffer);
+
+			if lines < (markview.configuration.max_length or 1000) then
+				parsed_content = markview.parser.init(buffer, markview.configuration);
+
+				markview.renderer.render(buffer, parsed_content, markview.configuration)
+			else
+				local cursor = vim.api.nvim_win_get_cursor(0);
+				local start = math.max(0, cursor[1] - (markview.configuration.render_range or 100));
+				local stop = math.min(lines, cursor[1] + (markview.configuration.render_range or 100));
+
+				parsed_content = markview.parser.parse_range(buffer, markview.configuration, start, stop);
+
+				markview.renderer.render(buffer, parsed_content, markview.configuration)
 			end
 
-			local windows = utils.find_attached_wins(event.buf);
+			if parsed_content and #parsed_content > 0 then
+				local windows = utils.find_attached_wins(event.buf);
 
-			local old_start, old_stop = _G.__markview_render_ranges[event.buf][1], _G.__markview_render_ranges[event.buf][2];
-			local parse_start, parse_stop = utils.get_cursor_range(event.buf, windows[1]);
+				for _, window in ipairs(windows) do
+					markview.keymaps.init(buffer, window, parsed_content, markview.configuration);
+				end
+			end
 
-			local prev_contents = markview.parser.parse_range(event.buf, markview.configuration, old_start, old_stop);
-			local partial_contents = markview.parser.parse_range(event.buf, markview.configuration, parse_start, parse_stop);
+			local cursor = vim.api.nvim_win_get_cursor(0);
+			local start = math.max(0, cursor[1] - 1);
+			local stop = math.min(lines, cursor[1]);
 
-			local current_range = markview.renderer.get_content_range(partial_contents);
+			local under_cursor = markview.parser.parse_range(event.buf, markview.configuration, start, stop);
+			local clear_range = markview.renderer.get_content_range(under_cursor);
 
-			if _G.__markview_render_ranges[event.buf] and vim.deep_equal(_G.__markview_render_ranges[event.buf], current_range) then
-				markview.renderer.clear_content_range(event.buf, partial_contents)
+			if not clear_range or not clear_range[1] or not clear_range[2] then
 				return;
 			end
 
-			markview.renderer.clear_content_range(event.buf, partial_contents)
-			markview.renderer.clear_content_range(event.buf, prev_contents);
-			markview.renderer.clear(event.buf, parse_start, parse_stop);
-
-			markview.renderer.render_in_range(event.buf, prev_contents, markview.configuration);
-			markview.renderer.update_range(event.buf, current_range);
+			markview.renderer.clear(event.buf, clear_range[1], clear_range[2])
 		end));
 	end
 })
diff --git a/lua/definitions.lua b/lua/definitions.lua
index ee5b70a..d27a29e 100644
--- a/lua/definitions.lua
+++ b/lua/definitions.lua
@@ -19,6 +19,12 @@
 --- List of modes where both raw & preview is shown
 ---@field hybrid_modes string[]?
 ---
+--- Max number of lines in a file to do full rendering
+---@field max_length number?
+---
+--- Number of lines to render on partial render mode
+---@field render_range number?
+---
 --- Callbacks for plugin states
 ---@field callbacks markview.config.callbacks?
 ---
@@ -65,6 +71,12 @@
 --- List of modes where both raw & preview is shown
 ---@field hybrid_modes string[]?
 ---
+--- Max number of lines in a file to do full rendering
+---@field max_length number?
+---
+--- Number of lines to render on partial render mode
+---@field render_range number?
+---
 --- Options for various plugins states
 ---@field callbacks markview.config.callbacks
 ---
diff --git a/lua/markview.lua b/lua/markview.lua
index bf87bf8..b40d8ff 100644
--- a/lua/markview.lua
+++ b/lua/markview.lua
@@ -41,8 +41,10 @@ markview.deep_merge = function (behavior, tbl_1, tbl_2)
 				for index, item in ipairs(value) do
 					if not markview.list_contains(tbl_1[key], item) then
 						table.insert(tbl_1[key], item);
-					else
+					elseif tbl_1[key][index] and type(tbl_1[key][index]) == "table" and type(item) == "table" then
 						tbl_1[key][index] = markview.deep_merge(behavior, tbl_1[key][index], item);
+					elseif not markview.list_contains(tbl_1[key], item) then
+						tbl_1[key][index] = item;
 					end
 				end
 			else
@@ -70,31 +72,49 @@ markview.hl_exits = function (hl_list, hl)
 	return false;
 end
 
+markview.added_hls = {};
+
+markview.remove_hls = function ()
+	if vim.tbl_isempty(markview.added_hls) then
+		return;
+	end
+
+	for _, hl in ipairs(markview.added_hls) do
+		if vim.fn.hlexists("Markview" .. hl) == 1 then
+			vim.api.nvim_set_hl(0, "Markview" .. hl, {});
+		end
+	end
+end
+
 markview.add_hls = function (obj)
-	local added = {};
+	markview.added_hls = {};
 	local use_hl = {};
 
 	for _, hl in ipairs(obj) do
 		if hl.output and type(hl.output) == "function" and pcall(hl.output) then
 			local _o = hl.output();
+			local _n = {};
 
 			for _, item in ipairs(_o) do
 				local exists, index = markview.hl_exits(use_hl, item);
 
 				if exists == true then
 					table.remove(use_hl, index);
+				else
+					table.insert(_n, item.group_name);
 				end
 			end
 
-			use_hl = vim.list_extend(use_hl, _o)
+			use_hl = vim.list_extend(use_hl, _o);
+			markview.added_hls = vim.list_extend(markview.added_hls, _n);
 		elseif hl.group_name and hl.value then
-			local contains, index = markview.list_contains(added, hl.group_name);
+			local contains, index = markview.list_contains(markview.added_hls, hl.group_name);
 
 			if contains == true and index then
 				use_hl[index] = hl;
 			else
 				table.insert(use_hl, hl)
-				table.insert(added, hl.group_name);
+				table.insert(markview.added_hls, hl.group_name);
 			end
 		end
 	end
@@ -124,16 +144,16 @@ markview.global_options = {};
 ---@type markview.config
 markview.configuration = {
 	callbacks = {
-		on_enable = function (buffer, window)
+		on_enable = function (_, window)
 			vim.wo[window].conceallevel = 2;
 			vim.wo[window].concealcursor = "nc";
 		end,
-		on_disable = function (buffer, window)
+		on_disable = function (_, window)
 			vim.wo[window].conceallevel = 0;
 			vim.wo[window].concealcursor = "";
 		end,
 
-		on_mode_change = function (buffer, window, mode)
+		on_mode_change = function (_, window, mode)
 			if vim.list_contains(markview.configuration.modes, mode) then
 				vim.wo[window].conceallevel = 2;
 			else
@@ -1594,11 +1614,17 @@ end, {
 })
 
 markview.setup = function (user_config)
+	if user_config and user_config.highlight_groups then
+		markview.configuration.highlight_groups = vim.list_extend(markview.configuration.highlight_groups, user_config.highlight_groups);
+		user_config.highlight_groups = nil;
+	end
+
 	---@type markview.config
 	-- Merged configuration tables
-	markview.configuration = markview.deep_merge("force", markview.configuration, user_config or {});
+	markview.configuration = vim.tbl_deep_extend("force", markview.configuration, user_config or {});
 
 	if vim.islist(markview.configuration.highlight_groups) then
+		markview.remove_hls();
 		markview.add_hls(markview.configuration.highlight_groups);
 	end
 
diff --git a/lua/markview/renderer.lua b/lua/markview/renderer.lua
index 3914131..6fa0c46 100644
--- a/lua/markview/renderer.lua
+++ b/lua/markview/renderer.lua
@@ -1725,6 +1725,8 @@ renderer.render = function (buffer, parsed_content, config_table, conceal_start,
 		_G.__markview_render_ranges[buffer] = {};
 	end
 
+	-- vim.print(#parsed_content)
+
 	for _, content in ipairs(_G.__markview_views[buffer]) do
 		local type = content.type;
 		local fold_closed = vim.fn.foldclosed(content.row_start + 1);