diff --git a/README.txt b/README.txt
index 14f19ef..98ba40e 100644
--- a/README.txt
+++ b/README.txt
@@ -86,7 +86,8 @@ its command line interface and options.
                         Alternatively give string names of your card like
                         gtx780ti or gt640#2 (matching 2nd gt640 in the PC).
 
-  -i, --intensity       GPU threads per call 0-31 (default: 0=auto)
+  -i, --intensity       GPU threads per call 8-31 (default: 0=auto)
+                        Decimals are allowed for fine tuning
   -f, --diff            Divide difficulty by this factor (std is 1)
   -v, --vote            Heavycoin block vote (default: 512)
   -o, --url=URL         URL of mining server
@@ -171,6 +172,7 @@ features.
                   v1.5.0
                   Upgrade compat jansson to 2.6 (for windows)
                   Add pool mining.set_extranonce support
+                  Allow intermediate intensity with decimals
                   Allow increased scan ranges (wip)
                   Some internal changes to use the C++ compiler
                   New API 1.2 with some new commands (read only)
diff --git a/ccminer.cpp b/ccminer.cpp
index 0b165ac..fd0c774 100644
--- a/ccminer.cpp
+++ b/ccminer.cpp
@@ -239,6 +239,7 @@ double   global_diff = 0.0;
 int opt_statsavg = 30;
 int opt_intensity = 0;
 uint32_t opt_work_size = 0; /* default */
+uint32_t opt_work_adds = 0;
 
 char *opt_api_allow = (char*) "127.0.0.1"; /* 0.0.0.0 for all ips */
 int opt_api_listen = 4068; /* 0 to disable */
@@ -287,7 +288,8 @@ Options:\n\
                         Device IDs start counting from 0! Alternatively takes\n\
                         string names of your cards like gtx780ti or gt640#2\n\
                         (matching 2nd gt640 in the PC)\n\
-  -i  --intensity=N     GPU intensity 0-31 (default: auto) \n\
+  -i  --intensity=N     GPU intensity 8-31 (default: auto) \n\
+                        Decimals are allowed for fine tuning \n\
   -f, --diff            Divide difficulty by this factor (std is 1) \n\
   -v, --vote=VOTE       block reward vote (for HeavyCoin)\n\
   -m, --trust-pool      trust the max block reward vote (maxvote) sent by the pool\n\
@@ -901,7 +903,7 @@ static void stratum_gen_work(struct stratum_ctx *sctx, struct work *work)
 		case ALGO_KECCAK:
 		case ALGO_BLAKECOIN:
 		case ALGO_WHC:
-			SHA256((uint8_t*)sctx->job.coinbase, sctx->job.coinbase_size, (uint8_t*)merkle_root);
+			SHA256((uchar*)sctx->job.coinbase, sctx->job.coinbase_size, (uchar*)merkle_root);
 			break;
 		default:
 			sha256d(merkle_root, sctx->job.coinbase, (int)sctx->job.coinbase_size);
@@ -1693,12 +1695,22 @@ static void parse_arg(int key, char *arg)
 		break;
 	}
 	case 'i':
-		v = atoi(arg);
+		d = atof(arg);
+		v = (uint32_t) d;
 		if (v < 0 || v > 31)
 			show_usage_and_exit(1);
 		opt_intensity = v;
-		if (v > 0) /* 0 = default */
+		if (v > 7) { /* 0 = default */
 			opt_work_size = (1 << v);
+			if ((d - v) > 0.0) {
+				opt_work_adds = (uint32_t) floor((d - v) * (1 << (v-8))) * 256;
+				opt_work_size += opt_work_adds;
+				applog(LOG_INFO, "Adding %u threads to intensity %u, %u cuda threads",
+					opt_work_adds, v, opt_work_size);
+			} else {
+				applog(LOG_INFO, "Intensity set to %u, %u cuda threads", v, opt_work_size);
+			}
+		}
 		break;
 	case 'D':
 		opt_debug = true;
diff --git a/miner.h b/miner.h
index 5fcea1c..52d538c 100644
--- a/miner.h
+++ b/miner.h
@@ -117,6 +117,14 @@ typedef unsigned char uchar;
 #define UINT32_MAX UINT_MAX
 #endif
 
+static inline bool is_windows(void) {
+#ifdef WIN32
+        return 1;
+#else
+        return 0;
+#endif
+}
+
 #if ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
 #define WANT_BUILTIN_BSWAP
 #else
diff --git a/x11/x11.cu b/x11/x11.cu
index 55d4dc0..ca2944c 100644
--- a/x11/x11.cu
+++ b/x11/x11.cu
@@ -129,16 +129,6 @@ extern "C" void x11hash(void *output, const void *input)
 	memcpy(output, hash, 32);
 }
 
-/* reduce by one default intensity on windows */
-static int is_windows(void)
-{
-#ifdef WIN32
-	return 1;
-#else
-	return 0;
-#endif
-}
-
 extern "C" int scanhash_x11(int thr_id, uint32_t *pdata,
     const uint32_t *ptarget, uint32_t max_nonce,
     unsigned long *hashes_done)
diff --git a/x13/x13.cu b/x13/x13.cu
index e9e3cd4..c174742 100644
--- a/x13/x13.cu
+++ b/x13/x13.cu
@@ -151,7 +151,8 @@ extern "C" int scanhash_x13(int thr_id, uint32_t *pdata,
 {
 	const uint32_t first_nonce = pdata[19];
 	static bool init[8] = { 0 };
-	int throughput = opt_work_size ? opt_work_size : (1 << 19); // 256*256*8;
+	int intensity = 19; // (device_sm[device_map[thr_id]] > 500 && !is_windows()) ? 20 : 19;
+	int throughput = opt_work_size ? opt_work_size : (1 << intensity); // 19=256*256*8;
 	throughput = min(throughput, (int)(max_nonce - first_nonce));
 
 	if (opt_benchmark)