Make SDK 2.6 warning and advice big and bold.

ocl.c

@@ -490,7 +490,10 @@ build:
 		(strstr(vbuff, "844.4") /* Linux 64 bit ATI 2.6 SDK */	||
 		 strstr(vbuff, "851.4") /* Windows 64 bit "" */		||
 		 strstr(vbuff, "831.4") /* Windows & Linux 32 bit "" */ )) {
-			applog(LOG_WARNING, "SDK 2.6 detected, using poclbm kernel");
+			applog(LOG_WARNING, "AMD OpenCL SDK 2.6 detected, using poclbm kernel");
+			applog(LOG_WARNING, "This SDK will give POOR PERFORMANCE on this device");
+			applog(LOG_WARNING, "To get best performance, remove any .bin files generated by cgminer,");
+			applog(LOG_WARNING, "downgrade your SDK to 2.1-2.5 and restart cgminer.");
 			clState->chosen_kernel = KL_POCLBM;
 			strcpy(filename, POCLBM_KERNNAME".cl");
 			strcpy(binaryfilename, POCLBM_KERNNAME);