diff --git a/README.md b/README.md
index 27a0e2c17..521cc1fd9 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,16 @@ At the moment, the [Windows 10 Insider Preview Build 15007](https://blogs.window
 
 Drivers indicate they can run DXIL by reporting support for Shader Model 6, possibly in experimental mode. To enable support in these cases, the [Developer mode](https://msdn.microsoft.com/windows/uwp/get-started/enable-your-device-for-development) setting must be enabled.
 
-By default, tests will run using the Windows Advanced Rasterization Platform (WARP) adapter. To get the correct version of WARP working, in addition to setting Developer mode, you should install the 'Graphics Tools' optional feature via the Settings app (click the 'Apps' icon, then the 'Manage optional features' link, then 'Add a feature', and select 'Graphics Tools' from the list).
+###Hardware Support
+
+Hardware GPU support for DXIL is provided by the following vendors:
+
+NVIDIA r378 drivers (r378.49 and later) provide experimental mode support for DXIL and shader model 6. This is an early beta version to enable developers to try out DXIL and the new shader model 6 features – Wave Math and int64. Only DXIL version 0.7 (beta) is accepted by the r378 driver.  Experimental mode support for DXIL v1.0 will be provided in a future driver release. 
+
+###Software Rendering
+
+in the absence of hardware support, tests will run using the Windows Advanced Rasterization Platform (WARP) adapter. To get the correct version of WARP working, in addition to setting Developer mode, you should install the 'Graphics Tools' optional feature via the Settings app (click the 'Apps' icon, then the 'Manage optional features' link, then 'Add a feature', and select 'Graphics Tools' from the list).
+
 
 For more information, see this [Wiki page](https://github.com/Microsoft/DirectXShaderCompiler/wiki/Running-Shaders).
 
diff --git a/utils/hct/hctbuild.cmd b/utils/hct/hctbuild.cmd
index 6c76e1cec..04cb9674c 100644
--- a/utils/hct/hctbuild.cmd
+++ b/utils/hct/hctbuild.cmd
@@ -116,6 +116,16 @@ set CMAKE_OPTS=%CMAKE_OPTS% -DCLANG_BUILD_EXAMPLES:BOOL=OFF
 set CMAKE_OPTS=%CMAKE_OPTS% -DLLVM_REQUIRES_RTTI:BOOL=ON
 set CMAKE_OPTS=%CMAKE_OPTS% -DCLANG_CL:BOOL=OFF
 
+rem This parameter is used with vcvarsall to force use of 64-bit build tools
+rem instead of 32-bit tools that run out of memory.
+if "%BUILD_ARCH%"=="Win32" (
+  set BUILD_TOOLS=amd64_x86
+) else if "%BUILD_ARCH%"=="x64" (
+  set BUILD_TOOLS=amd64
+) else if "%BUILD_ARCH%"=="ARM" (
+  set BUILD_TOOLS=amd64_arm
+)
+
 call :configandbuild %BUILD_CONFIG% %BUILD_ARCH% %HLSL_BLD_DIR% "%BUILD_GENERATOR%"
 if errorlevel 1 exit /b 1
 
@@ -215,7 +225,7 @@ rem 1 - config
 rem 2 - platform
 rem 3 - build directory
 setlocal
-call "%ProgramFiles(x86)%\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"
+call "%ProgramFiles(x86)%\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" %BUILD_TOOLS%
 rem Add /ds for a detailed summary at the end.
 MSBuild.exe /property:Configuration=%1 /property:Platform=%2 /maxcpucount %3\LLVM.sln
 if NOT "%ERRORLEVEL%"=="0" (
diff --git a/utils/hct/hctstart.cmd b/utils/hct/hctstart.cmd
index 0b1c8db93..6cd5a8a8e 100644
--- a/utils/hct/hctstart.cmd
+++ b/utils/hct/hctstart.cmd
@@ -27,6 +27,9 @@ shift /1
 
 :donearch
 echo Default architecture - set BUILD_ARCH=%BUILD_ARCH%
+rem Set the following environment variable globally, or start Visual Studio
+rem from this command line in order to use 64-bit tools.
+set PreferredToolArchitecture=x64
 
 if "%1"=="" (
   echo Source directory missing.