Use half the amount of threads for the signature checker

nano/node/nodeconfig.hpp

@@ -59,7 +59,7 @@ class node_config
 	unsigned io_threads{ std::max<unsigned> (4, std::thread::hardware_concurrency ()) };
 	unsigned network_threads{ std::max<unsigned> (4, std::thread::hardware_concurrency ()) };
 	unsigned work_threads{ std::max<unsigned> (4, std::thread::hardware_concurrency ()) };
-	unsigned signature_checker_threads{ (std::thread::hardware_concurrency () != 0) ? std::thread::hardware_concurrency () - 1 : 0 }; /* The calling thread does checks as well so remove it from the number of threads used */
+	unsigned signature_checker_threads{ (std::thread::hardware_concurrency () / 2 > 1) ? std::thread::hardware_concurrency () / 2 - 1 : 0 }; /* The calling thread does checks as well so remove it from the number of threads used */
 	bool enable_voting{ false };
 	unsigned bootstrap_connections{ 4 };
 	unsigned bootstrap_connections_max{ 64 };