diff --git a/src/H5Format.cpp b/src/H5Format.cpp
index 660ffc1..dc63080 100644
--- a/src/H5Format.cpp
+++ b/src/H5Format.cpp
@@ -58,7 +58,8 @@ H5::Group H5FormatUtils::create_group(H5::Group& target, const string& name)
     return target.createGroup(name.c_str());
 }
 
-const boost::any& H5FormatUtils::get_value_from_reference(const string& dataset_name, const boost::any& value_reference, const map<string, boost::any>& values)
+const boost::any& H5FormatUtils::get_value_from_reference(const string& dataset_name, 
+    const boost::any& value_reference, const unordered_map<string, boost::any>& values)
 {
     try {
         auto reference_string = boost::any_cast<string>(value_reference);
@@ -78,7 +79,8 @@ const boost::any& H5FormatUtils::get_value_from_reference(const string& dataset_
 
     } catch (const out_of_range& exception){
         stringstream error_message;
-        error_message << "Dataset " << dataset_name << " value reference " << boost::any_cast<string>(value_reference) << " not present in values map." << endl;
+        error_message << "Dataset " << dataset_name << " value reference " << boost::any_cast<string>(value_reference);
+        error_message << " not present in values map." << endl;
 
         throw runtime_error(error_message.str());
     }
@@ -123,7 +125,8 @@ const H5::PredType& H5FormatUtils::get_dataset_data_type(const string& type)
     }
 }
 
-H5::DataSet H5FormatUtils::write_dataset(H5::Group& target, const h5_dataset& dataset, const map<string, boost::any>& values)
+H5::DataSet H5FormatUtils::write_dataset(H5::Group& target, const h5_dataset& dataset, 
+    const unordered_map<string, boost::any>& values)
 {
     const string& name = dataset.name;
     boost::any value;
@@ -232,7 +235,8 @@ void H5FormatUtils::write_attribute(H5::H5Object& target, const string& name, in
     h5_attribute.write(data_type, &value);
 }
 
-void H5FormatUtils::write_attribute(H5::H5Object& target, const h5_attr& attribute, const map<string, boost::any>& values) 
+void H5FormatUtils::write_attribute(H5::H5Object& target, const h5_attr& attribute, 
+    const unordered_map<string, boost::any>& values) 
 {
     string name = attribute.name;
     boost::any value;
@@ -278,7 +282,8 @@ void H5FormatUtils::write_attribute(H5::H5Object& target, const h5_attr& attribu
     }
 }
 
-void H5FormatUtils::write_format_data(H5::Group& file_node, const h5_parent& format_node, const std::map<std::string, h5_value>& values) 
+void H5FormatUtils::write_format_data(H5::Group& file_node, const h5_parent& format_node, 
+    const std::unordered_map<std::string, h5_value>& values) 
 {
     H5::Group node_group = file_node;
 
@@ -322,12 +327,13 @@ void H5FormatUtils::write_format_data(H5::Group& file_node, const h5_parent& for
     }
 }
 
-void H5FormatUtils::write_format(H5::H5File& file, const H5Format& format, const std::map<std::string, h5_value>& input_values)
+void H5FormatUtils::write_format(H5::H5File& file, const H5Format& format, 
+    const std::unordered_map<std::string, h5_value>& input_values)
 {
     auto format_definition = format.get_format_definition();
     auto default_values = format.get_default_values();
 
-    map<string, boost::any> format_values(default_values);
+    auto format_values(default_values);
     
     format.add_input_values(format_values, input_values);
     format.add_calculated_values(format_values);
diff --git a/src/H5Format.hpp b/src/H5Format.hpp
index e803aeb..098bf25 100644
--- a/src/H5Format.hpp
+++ b/src/H5Format.hpp
@@ -3,7 +3,7 @@
 
 #include <string>
 #include <list>
-#include <map>
+#include <unordered_map>
 #include <H5Cpp.h>
 #include <memory>
 #include <tuple>
@@ -89,16 +89,16 @@ class H5Format
     public:
         virtual ~H5Format(){};
 
-        virtual const std::map<std::string, DATA_TYPE>& get_input_value_type() const = 0;
+        virtual const std::unordered_map<std::string, DATA_TYPE>& get_input_value_type() const = 0;
 
-        virtual const std::map<std::string, boost::any>& get_default_values() const = 0;
+        virtual const std::unordered_map<std::string, boost::any>& get_default_values() const = 0;
 
         virtual const h5_group& get_format_definition() const = 0;
 
-        virtual void add_calculated_values(std::map<std::string, boost::any>& values) const = 0;
+        virtual void add_calculated_values(std::unordered_map<std::string, boost::any>& values) const = 0;
 
-        virtual void add_input_values(std::map<std::string, boost::any>& values, 
-            const std::map<std::string, boost::any>& input_values) const = 0;
+        virtual void add_input_values(std::unordered_map<std::string, boost::any>& values, 
+            const std::unordered_map<std::string, boost::any>& input_values) const = 0;
 
         virtual std::string get_frames_dataset_name() const = 0;
 };
@@ -106,24 +106,36 @@ class H5Format
 namespace H5FormatUtils 
 {
     hsize_t expand_dataset(H5::DataSet& dataset, hsize_t frame_index, hsize_t dataset_increase_step);
+    
     void compact_dataset(H5::DataSet& dataset, hsize_t max_frame_index);
 
     H5::Group create_group(H5::Group& target, const std::string& name);
     const H5::PredType& get_dataset_data_type(const std::string& type);
 
-    H5::DataSet write_dataset(H5::Group& target, const h5_dataset& dataset, const std::map<std::string, boost::any>& values);
+    H5::DataSet write_dataset(H5::Group& target, const h5_dataset& dataset, 
+        const std::unordered_map<std::string, boost::any>& values);
+
     H5::DataSet write_dataset(H5::Group& target, const std::string& name, double value);
+
     H5::DataSet write_dataset(H5::Group& target, const std::string& name, int value);
+
     H5::DataSet write_dataset(H5::Group& target, const std::string& name, const std::string& value);
 
-    void write_attribute(H5::H5Object& target, const h5_attr& attribute, const std::map<std::string, boost::any>& values);
+    void write_attribute(H5::H5Object& target, const h5_attr& attribute, 
+        const std::unordered_map<std::string, boost::any>& values);
+
     void write_attribute(H5::H5Object& target, const std::string& name, const std::string& value);
+
     void write_attribute(H5::H5Object& target, const std::string& name, int value);
 
-    const boost::any& get_value_from_reference(const std::string& dataset_name, const boost::any& value_reference, const std::map<std::string, boost::any>& values);
+    const boost::any& get_value_from_reference(const std::string& dataset_name, 
+        const boost::any& value_reference, const std::unordered_map<std::string, boost::any>& values);
 
-    void write_format_data(H5::Group& file_node, const h5_parent& format_node, const std::map<std::string, h5_value>& values);
-    void write_format(H5::H5File& file, const H5Format& format, const std::map<std::string, h5_value>& input_values);
+    void write_format_data(H5::Group& file_node, const h5_parent& format_node, 
+        const std::unordered_map<std::string, h5_value>& values);
+
+    void write_format(H5::H5File& file, const H5Format& format, 
+        const std::unordered_map<std::string, h5_value>& input_values);
 };
 
 #endif
\ No newline at end of file
diff --git a/src/RestApi.cpp b/src/RestApi.cpp
index 2cce72b..105e193 100644
--- a/src/RestApi.cpp
+++ b/src/RestApi.cpp
@@ -97,7 +97,7 @@ void RestApi::start_rest_api(WriterManager& writer_manager, uint16_t port)
             return result;
         } else {
             auto request_parameters = crow::json::load(req.body);
-            std::map<std::string, boost::any> new_parameters;
+            std::unordered_map<std::string, boost::any> new_parameters;
 
             for (const auto& item : request_parameters) {
                 string parameter_name = item.key();
diff --git a/src/WriterManager.cpp b/src/WriterManager.cpp
index 4c4e053..3a74d97 100644
--- a/src/WriterManager.cpp
+++ b/src/WriterManager.cpp
@@ -5,9 +5,10 @@
 
 using namespace std;
 
-WriterManager::WriterManager(const map<string, DATA_TYPE>& parameters_type, const string& output_file, uint64_t n_frames):
-    parameters_type(parameters_type), output_file(output_file), n_frames(n_frames), running_flag(true), killed_flag(false), 
-    n_received_frames(0), n_written_frames(0), n_lost_frames(0)
+WriterManager::WriterManager(const unordered_map<string, DATA_TYPE>& parameters_type, 
+    const string& output_file, uint64_t n_frames):
+        parameters_type(parameters_type), output_file(output_file), n_frames(n_frames), 
+        running_flag(true), killed_flag(false), n_received_frames(0), n_written_frames(0), n_lost_frames(0)
 {
     #ifdef DEBUG_OUTPUT
         cout << "[WriterManager::WriterManager] Writer manager for n_frames " << n_frames << endl;
@@ -54,9 +55,9 @@ string WriterManager::get_output_file() const
     return output_file;
 }
 
-map<string, uint64_t> WriterManager::get_statistics() const
+unordered_map<string, uint64_t> WriterManager::get_statistics() const
 {
-    map<string, uint64_t> result = {{"n_received_frames", n_received_frames.load()},
+    unordered_map<string, uint64_t> result = {{"n_received_frames", n_received_frames.load()},
                                     {"n_written_frames", n_written_frames.load()},
                                     {"n_lost_frames", n_lost_frames.load()},
                                     {"total_expected_frames", n_frames}};
@@ -64,14 +65,14 @@ map<string, uint64_t> WriterManager::get_statistics() const
     return result;
 }
 
-map<string, boost::any> WriterManager::get_parameters()
+unordered_map<string, boost::any> WriterManager::get_parameters()
 {
     lock_guard<mutex> lock(parameters_mutex);
 
     return parameters;
 }
 
-void WriterManager::set_parameters(const map<string, boost::any>& new_parameters)
+void WriterManager::set_parameters(const unordered_map<string, boost::any>& new_parameters)
 {
     lock_guard<mutex> lock(parameters_mutex);
 
@@ -96,7 +97,7 @@ void WriterManager::set_parameters(const map<string, boost::any>& new_parameters
     #endif
 }
 
-const map<string, DATA_TYPE>& WriterManager::get_parameters_type() const
+const unordered_map<string, DATA_TYPE>& WriterManager::get_parameters_type() const
 {
     return parameters_type;
 }
diff --git a/src/WriterManager.hpp b/src/WriterManager.hpp
index ab680b6..3debdac 100644
--- a/src/WriterManager.hpp
+++ b/src/WriterManager.hpp
@@ -1,7 +1,7 @@
 #ifndef WRITERMANAGER_H
 #define WRITERMANAGER_H
 
-#include <map>
+#include <unordered_map>
 #include <string>
 #include <atomic>
 #include <mutex>
@@ -12,11 +12,11 @@
 class WriterManager
 {
     
-    std::map<std::string, boost::any> parameters = {};
+    std::unordered_map<std::string, boost::any> parameters = {};
     std::mutex parameters_mutex;
 
     // Initialize in constructor.
-    const std::map<std::string, DATA_TYPE>& parameters_type;
+    const std::unordered_map<std::string, DATA_TYPE>& parameters_type;
     std::string output_file;
     size_t n_frames;
     std::atomic_bool running_flag;
@@ -26,7 +26,7 @@ class WriterManager
     std::atomic<uint64_t> n_lost_frames;
 
     public:
-        WriterManager(const std::map<std::string, DATA_TYPE>& parameters_type, const std::string& output_file, uint64_t n_frames=0);
+        WriterManager(const std::unordered_map<std::string, DATA_TYPE>& parameters_type, const std::string& output_file, uint64_t n_frames=0);
         virtual ~WriterManager();
 
         void stop();
@@ -37,11 +37,11 @@ class WriterManager
         bool are_all_parameters_set();
         std::string get_output_file() const;
 
-        const std::map<std::string, DATA_TYPE>& get_parameters_type() const;
-        std::map<std::string, boost::any> get_parameters();
-        void set_parameters(const std::map<std::string, boost::any>& new_parameters);
+        const std::unordered_map<std::string, DATA_TYPE>& get_parameters_type() const;
+        std::unordered_map<std::string, boost::any> get_parameters();
+        void set_parameters(const std::unordered_map<std::string, boost::any>& new_parameters);
         
-        std::map<std::string, uint64_t> get_statistics() const;
+        std::unordered_map<std::string, uint64_t> get_statistics() const;
         void received_frame(size_t frame_index);
         void written_frame(size_t frame_index);
         void lost_frame(size_t frame_index);
diff --git a/src/format/NXmxFormat.cpp b/src/format/NXmxFormat.cpp
index 7c7f1a8..7c65628 100644
--- a/src/format/NXmxFormat.cpp
+++ b/src/format/NXmxFormat.cpp
@@ -11,8 +11,8 @@ using s_ptr = shared_ptr<h5_base>;
 
 class NXmxFormat : public H5Format
 {
-    shared_ptr<map<string, DATA_TYPE>> input_value_type = NULL;
-    shared_ptr<map<string, boost::any>> default_values = NULL;
+    shared_ptr<unordered_map<string, DATA_TYPE>> input_value_type = NULL;
+    shared_ptr<unordered_map<string, boost::any>> default_values = NULL;
     shared_ptr<h5_group> file_format = NULL;
 
     public:
@@ -23,7 +23,7 @@ class NXmxFormat : public H5Format
             // Input values definition type. 
             // Which type should be the parameters you receive over the REST api.
             input_value_type.reset(
-            new map<string, DATA_TYPE>({
+            new unordered_map<string, DATA_TYPE>({
                 {"sl2wv", NX_FLOAT},
                 {"sl0ch", NX_FLOAT},
                 {"sl2wh", NX_FLOAT},
@@ -94,7 +94,7 @@ class NXmxFormat : public H5Format
             }));
 
             // Default values used in the file format.
-            default_values.reset(new std::map<string, boost::any>(
+            default_values.reset(new std::unordered_map<string, boost::any>(
             {    
                 {"filter_set/description", "The filter set consists of 4 linear stages, each with five filter positions. Additionally each one allows for an out position to allow no filtering."},
                 {"XBPM4/calibration_date", "???"},
@@ -905,12 +905,12 @@ class NXmxFormat : public H5Format
             return *file_format;
         }
 
-        const map<string, boost::any>& get_default_values() const override {
+        const unordered_map<string, boost::any>& get_default_values() const override {
             return *default_values;
         }
 
-        void add_calculated_values(map<string, boost::any>& values) const override {
-            map<string, string> input_mapping = {
+        void add_calculated_values(unordered_map<string, boost::any>& values) const override {
+            unordered_map<string, string> input_mapping = {
                 {"source/distance", "input/samz"},
                 {"slit_0/distance", "input/samz"},
                 {"slit_1/distance", "input/samz"},
@@ -924,7 +924,7 @@ class NXmxFormat : public H5Format
                 {"filter_set/attenuator_transmission", "input/ftrans"},
             };
             
-            map<string, function<double(double)>> functions = {
+            unordered_map<string, function<double(double)>> functions = {
                 {"source/distance", [](double x) -> double { return -33800 - x;}},
                 {"slit_0/distance", [](double x) -> double { return -33800 + 12100 - x;}},
                 {"slit_1/distance", [](double x) -> double { return -33800 + 26000 - x;}},
@@ -969,8 +969,9 @@ class NXmxFormat : public H5Format
             }
         }
 
-        void add_input_values(map<string, boost::any>& values, const map<string, boost::any>& input_values) const override {
-            map<string, list<string>> input_mapping = {
+        void add_input_values(unordered_map<string, boost::any>& values, 
+            const unordered_map<string, boost::any>& input_values) const override {
+            unordered_map<string, list<string>> input_mapping = {
                 {"sl2wv", {"slit_2/y_gap"}},
                 {"sl0ch", {"slit_0/x_translation"}},
                 {"sl2wh", {"slit_2/x_gap"}},
@@ -1047,7 +1048,7 @@ class NXmxFormat : public H5Format
             }
         }
 
-        const std::map<string, DATA_TYPE>& get_input_value_type() const override {
+        const std::unordered_map<string, DATA_TYPE>& get_input_value_type() const override {
             return *input_value_type;
         }