Slightly tweaked formula to selected the number of instances based on CPU count. Maximum value is now 16.

doc/Changelog.html

@@ -21,6 +21,7 @@ a:visited { color: #0000EE; }
 <li>Updated LAME encoder to v3.99.2 Final (2011-11-18), compiled with ICL 12.1.7 and MSVC 10.0 (<a href="http://lame.cvs.sourceforge.net/viewvc/lame/lame/doc/html/history.html?revision=1.134" target="_blank">details</a>)
 <li>Updated MediaInfo to v0.7.51+ (2011-11-19), compiled with ICL 12.1.6 and MSVC 10.0
 <li>Implemented coalescing of update signals in order to reduce the CPU usage of the LameXP process
+<li>Run more than four instances in parallel on systems with more than four CPU cores (<a href="FAQ.html#89cbd3d0" target="_blank">details</a>)
 </ul><br>
 
 <a name="4.03"></a>Changes between v4.02 and v4.03:<br><ul>

doc/FAQ.html

@@ -479,21 +479,21 @@ mapping! Instead a custom-made 'cubic spline' function is used to map the number
 number of instances. This function has the following properties: On systems with at most four CPU cores, the<br>
 maximum number of parallel instances will be identical to the number of CPU cores. On systems with eight CPU<br>
 cores, the maximum number of parallel instances is six. On systems with 16 cores, the maximum number of<br>
-parallel instances is eight. On systems with 32 cores, the maximum number of parallel instances is ten. And<br>
+parallel instances is eight. On systems with 32 cores, the maximum number of parallel instances is eleven.<br>
-on systems with 64 cores, the maximum number of parallel instances is twelve. Twelve is the upper limit.<br>
+And on systems with 64 cores, the maximum number of parallel instances is 16. 16 is the upper limit.<br>
 <br>
-<a href="http://img265.imageshack.us/img265/9200/cpucoresmapping.png" target="_blank"><img src="http://img265.imageshack.us/img265/9200/cpucoresmapping.th.png" border="0" alt="thumb"></a><br>
+<a href="http://img685.imageshack.us/img685/9453/cpucoresmappingnew.png" target="_blank"><img src="http://img685.imageshack.us/img685/9453/cpucoresmappingnew.th.png" border="0" alt="thumb"></a><br>
 <br>
 You may wonder why LameXP doesn't always create one instance for each CPU core. In theory, the more instances<br>
-we create, the more CPU cores can be utilized. In reality, however, there are more "shared" resources on the<br>
+we create, the more CPU cores can be utilized. In reality, however, there are some "shared" resources on the<br>
-computer. And, the more instances we run in parallel, the more processes will be competing for the shared<br>
+computer. And, the more instances we run in parallel, the more processes will be competing for these shared<br>
 resources! More specifically, the amount of main memory (RAM) is limited. Creating a huge number of instances<br>
 in parallel can easily use up all RAM, which will cause the operating system to make heavy use of the page<br>
 file. This can result in HDD thrasing and may significantly hurt the overall performance! But even when there<br>
 is enough RAM available on the system, each encoder or decoder instance needs to access the HDD, e.g. for<br>
 reading the input file and for writing the output file. Thus too many instances will cause an I/O bottleneck!<br>
 If, however, you think that LameXP's choice of the number of parallel instances is too conservative, you may<br>
-overwrite the number of parallel instances on the "Advanced Options" tab. The upper limit is 16.<br>
+overwrite the number of parallel instances on the "Advanced Options" tab. The upper limit is 16 for now.<br>
 <br>
 Finally, note that LameXP only controls the number of instances that will run in parallel, but it does NOT<br>
 control how many threads an individual instance will create! Some encoders use "built-in" multi-threading and<br>

src/Config.h

@@ -30,7 +30,7 @@
 #define VER_LAMEXP_MINOR_LO					4
 #define VER_LAMEXP_TYPE						Alpha
 #define VER_LAMEXP_PATCH					4
-#define VER_LAMEXP_BUILD					792
+#define VER_LAMEXP_BUILD					793
 
 ///////////////////////////////////////////////////////////////////////////////
 // Tool versions (minimum expected versions!)

src/Dialog_Processing.cpp

@@ -987,18 +987,18 @@ bool ProcessingDialog::shutdownComputer(void)
 
 static int cores2instances(int cores)
 {
-	//This function was approximated as a "cubic spline" with sampling points at:
+	//This function is a "cubic spline" with sampling points at:
-	//(1,1); (2,2); (4,4); (8,6); (16,8); (32,10); (64,12)
+	//(1,1); (2,2); (4,4); (8,6); (16,8); (32,11); (64,16)
 	static const double LUT[8][5] =
 	{
-		{ 1.0,  0.01440972, -0.04322917, 1.02881944,  0.00000000},
+		{ 1.0,  0.014353554, -0.043060662, 1.028707108,  0.000000000},
-		{ 2.0, -0.02881944,  0.21614583, 0.51006944,  0.34583333},
+		{ 2.0, -0.028707108,  0.215303309, 0.511979167,  0.344485294},
-		{ 4.0,  0.01017795, -0.25182292, 2.38194444, -2.15000000},
+		{ 4.0,  0.010016468, -0.249379596, 2.370710784, -2.133823529},
-		{ 8.0,  0.00005425, -0.00885417, 0.43819444,  3.03333333},
+		{ 8.0,  0.000282437, -0.015762868, 0.501776961,  2.850000000},
-		{16.0,  0.00011122, -0.01158854, 0.48194444,  2.80000000},
+		{16.0,  0.000033270, -0.003802849, 0.310416667,  3.870588235},
-		{32.0,  0.00000949, -0.00182292, 0.16944444,  6.13333333},
+		{32.0,  0.000006343, -0.001217831, 0.227696078,  4.752941176},
-		{64.0,  0.00000000,  0.00000000, 0.00000000, 12.00000000},
+		{64.0,  0.000000000,  0.000000000, 0.000000000, 16.000000000},
-		{DBL_MAX}
+		{DBL_MAX, 0.0, 0.0, 0.0, 0.0}
 	};
 
 	double x = abs(static_cast<double>(cores)), y = 1.0;