reworded a bit based on prior thread with product team

mikeblome · mikeblome · commit fa669e44529d · 2018-09-26T18:45:32.000-07:00
diff --git a/docs/build/reference/running-lib.md b/docs/build/reference/running-lib.md
@@ -1,7 +1,7 @@
 ---
 title: "Running LIB | Microsoft Docs"
 ms.custom: ""
-ms.date: "09/24/2018"
+ms.date: "09/27/2018"
 ms.technology: ["cpp-tools"]
 ms.topic: "reference"
 f1_keywords: ["VC.Project.VCLibrarianTool.TargetMachine", "Lib", "VC.Project.VCLibrarianTool.PrintProgress", "VC.Project.VCLibrarianTool.SuppressStartupBanner"]
@@ -49,7 +49,7 @@ For more information about **/ERRORREPORT**, see [/errorReport (Report Internal
 
 > **/LTCG**
 
-**/LTCG** enables *link-time code generation*, which enables build optimizations beyond what the compiler can provide for a single translation unit. **/LTCG** requires cooperation between the compiler ([cl.exe](compiler-options.md)), LIB, and the linker ([LINK](linker-options.md)). Use this option to tell LIB that the inputs from cl.exe include object files that were generated by using the [/GL](gl-whole-program-optimization.md) compiler option. If LIB.exe encounters such inputs and **/LTCG** is not specified, it will restart with /LTCG enabled after displaying an informational message.
+"LTCG" stands for *link-time code generation*, which enables build optimizations beyond what the compiler can provide for a single translation unit. The feature requires cooperation between the compiler ([cl.exe](compiler-options.md)), LIB, and the linker ([LINK](linker-options.md)). For LIB, the **/LTCG** option specifies that the inputs from cl.exe include object files that were generated by using the [/GL](gl-whole-program-optimization.md) compiler option. If LIB.exe encounters such inputs and **/LTCG** is not specified, it will restart with /LTCG enabled after displaying an informational message. Although it is not necessary to explicitly set this option, it speeds up build performance to do so because LIB does not have to restart itself.
 
 In the build process, the output from LIB is sent to LINK. LINK has its own separate **/LTCG** option which is used to perform various optimizations, including whole-program optimization and profile-guided optimization (PGO) instrumentation. For more information about the LINK option, see [/LTCG](ltcg-link-time-code-generation.md).
 
