diff --git a/xc7/arch.cc b/xc7/arch.cc
index f33c72ee..94afaf1b 100644
--- a/xc7/arch.cc
+++ b/xc7/arch.cc
@@ -232,6 +232,7 @@ TorcInfo::TorcInfo(BaseCtx *ctx, const std::string &inDeviceName, const std::str
     wire_to_tilewire.shrink_to_fit();
     wire_to_delay.shrink_to_fit();
     num_wires = wire_to_tilewire.size();
+    wire_is_clk.resize(num_wires);
 
     wire_to_pips_downhill.resize(num_wires);
     // std::unordered_map<Arc, int> arc_to_pip;
@@ -256,9 +257,12 @@ TorcInfo::TorcInfo(BaseCtx *ctx, const std::string &inDeviceName, const std::str
 
         auto &pips = wire_to_pips_downhill[w.index];
         pips.reserve(arcs.size());
-        const bool clk_tile = boost::starts_with(tileTypeName, "CMT") || boost::starts_with(tileTypeName, "CLK");
+        const bool clk_tile = boost::starts_with(tileTypeName, "CLK");
         const bool int_tile = boost::starts_with(tileTypeName, "INT");
 
+        if (clk_tile)
+            wire_is_clk[w.index] = clk_tile;
+
         for (const auto &a : arcs) {
             // Disable BUFG I0 -> O routethrough
             if (clk_tile) {
diff --git a/xc7/arch.h b/xc7/arch.h
index 1d4af94f..01a9475b 100644
--- a/xc7/arch.h
+++ b/xc7/arch.h
@@ -324,6 +324,7 @@ struct TorcInfo
     std::vector<WireId> pip_to_dst_wire;
     int width;
     int height;
+    std::vector<bool> wire_is_clk;
 
     TorcInfo(const std::string &inDeviceName, const std::string &inPackageName);
 private:
@@ -347,6 +348,7 @@ private:
         ar & pip_to_arc;
         ar & num_pips;
         ar & pip_to_dst_wire;
+        ar & wire_is_clk;
     }
 };
 extern std::unique_ptr<const TorcInfo> torc_info;
diff --git a/xc7/delay.cc b/xc7/delay.cc
index 6606fc37..a2ffc870 100644
--- a/xc7/delay.cc
+++ b/xc7/delay.cc
@@ -104,26 +104,37 @@ delay_t Arch::estimateDelay(WireId src, WireId dst) const
     const auto &src_info = torc_info->tiles.getTileInfo(src_tw.getTileIndex());
     const auto &dst_tw = torc_info->wire_to_tilewire[dst.index];
     const auto &dst_info = torc_info->tiles.getTileInfo(dst_tw.getTileIndex());
-    auto abs_delta_x = abs(src_info.getCol() - dst_info.getCol());
-    auto abs_delta_y = abs(src_info.getRow() - dst_info.getRow());
+
+    if (!torc_info->wire_is_clk[src.index]) {
+        auto abs_delta_x = abs(src_info.getCol() - dst_info.getCol());
+        auto abs_delta_y = abs(src_info.getRow() - dst_info.getRow());
 #if 1
-    auto div_LH = std::div(abs_delta_x, 12);
-    auto div_LV = std::div(abs_delta_y, 18);
-    auto div_LVB = std::div(div_LV.rem, 12);
-    auto div_H6 = std::div(div_LH.rem, 6);
-    auto div_V6 = std::div(div_LVB.rem, 6);
-    auto div_H4 = std::div(div_H6.rem, 4);
-    auto div_V4 = std::div(div_V6.rem, 4);
-    auto div_H2 = std::div(div_H4.rem, 2);
-    auto div_V2 = std::div(div_V4.rem, 2);
-    auto num_H1 = div_H2.rem;
-    auto num_V1 = div_V2.rem;
-    return div_LH.quot * 360 + div_LVB.quot * 300 + div_LV.quot * 350 +
-           (div_H6.quot + div_H4.quot + div_V6.quot + div_V4.quot) * 210 + (div_H2.quot + div_V2.quot) * 170 +
-           (num_H1 + num_V1) * 150;
+        auto div_LH = std::div(abs_delta_x, 12);
+        auto div_LV = std::div(abs_delta_y, 18);
+        auto div_LVB = std::div(div_LV.rem, 12);
+        auto div_H6 = std::div(div_LH.rem, 6);
+        auto div_V6 = std::div(div_LVB.rem, 6);
+        auto div_H4 = std::div(div_H6.rem, 4);
+        auto div_V4 = std::div(div_V6.rem, 4);
+        auto div_H2 = std::div(div_H4.rem, 2);
+        auto div_V2 = std::div(div_V4.rem, 2);
+        auto num_H1 = div_H2.rem;
+        auto num_V1 = div_V2.rem;
+        return div_LH.quot * 360 + div_LVB.quot * 300 + div_LV.quot * 350 +
+               (div_H6.quot + div_H4.quot + div_V6.quot + div_V4.quot) * 210 + (div_H2.quot + div_V2.quot) * 170 +
+               (num_H1 + num_V1) * 150;
 #else
-    return std::max(150, 33 * abs_delta_x + 66 * abs_delta_y);
+        return std::max(150, 33 * abs_delta_x + 66 * abs_delta_y);
 #endif
+    }
+    else {
+        auto src_y = src_info.getRow();
+        auto dst_y = dst_info.getRow();
+        src_y -= src_y % 50;
+        dst_y -= dst_y % 50;
+        auto abs_delta_y = abs(src_y - dst_y);
+        return abs_delta_y * 64; // arbitrary factor
+    }
 }
 
 delay_t Arch::predictDelay(const NetInfo *net_info, const PortRef &sink) const