diff --git a/modules/imgproc/perf/opencl/perf_filters.cpp b/modules/imgproc/perf/opencl/perf_filters.cpp
index d4dfbe0cc6..27dc09f1a8 100644
--- a/modules/imgproc/perf/opencl/perf_filters.cpp
+++ b/modules/imgproc/perf/opencl/perf_filters.cpp
@@ -246,14 +246,14 @@ OCL_PERF_TEST_P(GaussianBlurFixture, GaussianBlur,
     const FilterParams params = GetParam();
     const Size srcSize = get<0>(params);
     const int type = get<1>(params), ksize = get<2>(params);
-    const double eps = CV_MAT_DEPTH(type) <= CV_32S ? 1 + DBL_EPSILON : 3e-4;
+    const double eps = CV_MAT_DEPTH(type) <= CV_32S ? 2 + DBL_EPSILON : 3e-4;
 
     checkDeviceMaxMemoryAllocSize(srcSize, type);
 
     UMat src(srcSize, type), dst(srcSize, type);
     declare.in(src, WARMUP_RNG).out(dst);
 
-    OCL_TEST_CYCLE() cv::GaussianBlur(src, dst, Size(ksize, ksize), 0);
+    OCL_TEST_CYCLE() cv::GaussianBlur(src, dst, Size(ksize, ksize), 1, 1, cv::BORDER_CONSTANT);
 
     SANITY_CHECK(dst, eps);
 }
diff --git a/modules/imgproc/src/smooth.cpp b/modules/imgproc/src/smooth.cpp
index e0320fac3a..a14305cabe 100644
--- a/modules/imgproc/src/smooth.cpp
+++ b/modules/imgproc/src/smooth.cpp
@@ -1174,7 +1174,7 @@ void cv::GaussianBlur( InputArray _src, OutputArray _dst, Size ksize,
         return;
 #endif
 
-#if IPP_VERSION_X100 >= 801
+#if IPP_VERSION_X100 >= 801 && 0 // these functions are slower in IPP 8.1
     int depth = CV_MAT_DEPTH(type), cn = CV_MAT_CN(type);
 
     if ((depth == CV_8U || depth == CV_16U || depth == CV_16S || depth == CV_32F) && (cn == 1 || cn == 3) &&