diff --git a/.github/workflows/main/installDependencies.py b/.github/workflows/main/installDependencies.py
index 375b46d613a..21acacf4a15 100755
--- a/.github/workflows/main/installDependencies.py
+++ b/.github/workflows/main/installDependencies.py
@@ -49,7 +49,7 @@
 
 # Determine default archive URL.
 
-defaultURL = "https://github.com/GafferHQ/dependencies/releases/download/8.0.0a9/gafferDependencies-8.0.0a9-{platform}{buildEnvironment}.{extension}"
+defaultURL = "https://github.com/GafferHQ/dependencies/releases/download/8.0.0a10/gafferDependencies-8.0.0a10-{platform}{buildEnvironment}.{extension}"
 
 # Parse command line arguments.
 
diff --git a/Changes.md b/Changes.md
index 5e5953b52fd..bf31a21c240 100644
--- a/Changes.md
+++ b/Changes.md
@@ -1,6 +1,11 @@
 1.4.x.x (relative to 1.4.0.0b6)
 =======
 
+Features
+--------
+
+- Cycles : Added support for CUDA and Optix devices on Windows [^1].
+
 Improvements
 ------------
 
diff --git a/SConstruct b/SConstruct
index 265463c3d23..c010cc56f0e 100644
--- a/SConstruct
+++ b/SConstruct
@@ -1360,7 +1360,7 @@ libraries = {
 			"LIBS" : [
 				"Gaffer", "GafferScene", "GafferDispatch", "GafferBindings", "GafferCycles", "IECoreScene",
 				"cycles_session", "cycles_scene", "cycles_graph", "cycles_bvh", "cycles_device", "cycles_kernel", "cycles_kernel_osl",
-				"cycles_integrator", "cycles_util", "cycles_subd", "extern_sky",
+				"cycles_integrator", "cycles_util", "cycles_subd", "extern_sky", "extern_cuew",
 				"OpenImageIO$OIIO_LIB_SUFFIX", "OpenImageIO_Util$OIIO_LIB_SUFFIX", "oslexec$OSL_LIB_SUFFIX", "openvdb$VDB_LIB_SUFFIX",
 				"oslquery$OSL_LIB_SUFFIX", "Alembic", "osdCPU", "OpenColorIO$OCIO_LIB_SUFFIX", "embree4", "Iex", "openpgl",
 			],
@@ -1503,11 +1503,16 @@ for library in ( "GafferUI", ) :
 
 if env["PLATFORM"] == "win32" :
 
-	for library in ( "Gaffer", ) :
+	for library in ( "Gaffer", "GafferCycles", ) :
 
 		libraries[library].setdefault( "envAppends", {} )
 		libraries[library]["envAppends"].setdefault( "LIBS", [] ).extend( [ "Advapi32" ] )
 
+	for library in ( "GafferCycles", ) :
+
+		libraries[library].setdefault( "pythonEnvAppends", {} )
+		libraries[library]["pythonEnvAppends"].setdefault( "LIBS", [] ).extend( [ "Advapi32" ] )
+
 else :
 
 	libraries["GafferCycles"]["envAppends"]["LIBS"].extend( [ "dl" ] )
diff --git a/include/GafferCycles/IECoreCyclesPreview/IECoreCycles.h b/include/GafferCycles/IECoreCyclesPreview/IECoreCycles.h
index 079da39b707..b057be7757c 100644
--- a/include/GafferCycles/IECoreCyclesPreview/IECoreCycles.h
+++ b/include/GafferCycles/IECoreCyclesPreview/IECoreCycles.h
@@ -47,6 +47,10 @@ IECORE_POP_DEFAULT_VISIBILITY
 namespace IECoreCycles
 {
 
+/// Returns the value of the `CYCLES_ROOT` environment variable, or
+/// and empty string if the variable is not defined.
+IECORECYCLES_API const char *cyclesRoot();
+
 /// Initialises the library using the CYCLES_ROOT environment
 /// variable, which should point to the root of a Cycles installation.
 IECORECYCLES_API bool init();
diff --git a/src/GafferCycles/IECoreCyclesPreview/IECoreCycles.cpp b/src/GafferCycles/IECoreCyclesPreview/IECoreCycles.cpp
index bae2a7114ae..10e68241369 100644
--- a/src/GafferCycles/IECoreCyclesPreview/IECoreCycles.cpp
+++ b/src/GafferCycles/IECoreCyclesPreview/IECoreCycles.cpp
@@ -56,23 +56,28 @@ std::string cyclesVersion = CYCLES_VERSION_STRING;
 namespace IECoreCycles
 {
 
-bool init()
+const char *cyclesRoot()
 {
 	const char *cyclesRoot = getenv( "CYCLES_ROOT" );
 	if( !cyclesRoot )
 	{
 		IECore::msg( IECore::Msg::Error, "IECoreCycles::init", "CYCLES_ROOT environment variable not set" );
-		return false;
+		return "";
 	}
+	return cyclesRoot;
+}
 
-	auto kernelFile = std::filesystem::path( cyclesRoot ) / "source" / "kernel" / "types.h";
+bool init()
+{
+	const char *cyclesRootValue = cyclesRoot();
+	auto kernelFile = std::filesystem::path( cyclesRootValue ) / "source" / "kernel" / "types.h";
 	if( !std::filesystem::is_regular_file( kernelFile ) )
 	{
 		IECore::msg( IECore::Msg::Error, "IECoreCycles::init", fmt::format( "File \"{}\" not found", kernelFile ) );
 		return false;
 	}
 
-	ccl::path_init( cyclesRoot );
+	ccl::path_init( cyclesRootValue );
 
 	// This is a global thing for logging
 	const char* argv[] = { "-", "v", "1" };
diff --git a/src/GafferCyclesModule/GafferCyclesModule.cpp b/src/GafferCyclesModule/GafferCyclesModule.cpp
index b7612d7f788..2e568866da7 100644
--- a/src/GafferCyclesModule/GafferCyclesModule.cpp
+++ b/src/GafferCyclesModule/GafferCyclesModule.cpp
@@ -58,6 +58,7 @@
 #include "device/device.h"
 #include "graph/node.h"
 #include "util/openimagedenoise.h"
+#include "util/path.h"
 
 namespace py = boost::python;
 using namespace boost::python;
@@ -453,6 +454,10 @@ BOOST_PYTHON_MODULE( _GafferCycles )
 
 	IECoreCycles::init();
 
+	// Must be initialized to ensure the statically linked Cycles module
+	// we are linked to can find the binaries for GPU rendering.
+	ccl::path_init( IECoreCycles::cyclesRoot() );
+
 	py::scope().attr( "devices" ) = getDevices();
 	py::scope().attr( "nodes" ) = getNodes();
 	py::scope().attr( "shaders" ) = getShaders();