docs: more details about Viewperf 12 medical-01 test issues
diff --git a/docs/viewperf.html b/docs/viewperf.html
index 6b63b94..a60a44f 100644
--- a/docs/viewperf.html
+++ b/docs/viewperf.html
@@ -329,6 +329,13 @@
<code>#version 120</code> at the top of the shader code.
So, the shader does not compile and all that's rendered is plain white polygons.
</p>
+<p>
+Also, the test tries to create a very large 3D texture that may exceed
+the device driver's limit.
+When this happens, the glTexImage3D call fails and all that's rendered is
+a white box.
+</p>
+
<h3>showcase-01</h3>