diff --git a/pool.cpp b/pool.cpp
index 3efca4aa..17e37c57 100644
--- a/pool.cpp
+++ b/pool.cpp
@@ -77,8 +77,10 @@ long long addpool(struct memfile *poolfile, struct memfile *treefile, const char
 		}
 	}
 
-	// Size of memory divided by 5 from observation of OOM errors on ECS
-	if ((size_t) (poolfile->off + treefile->off) > memsize / CPUS / 5) {
+	// Size of memory divided by 10 from observation of OOM errors (when supposedly
+	// 20% of memory is full) and onset of thrashing (when supposedly 15% of memory
+	// is full) on ECS.
+	if ((size_t) (poolfile->off + treefile->off) > memsize / CPUS / 10) {
 		// If the pool and search tree get to be larger than physical memory,
 		// then searching will start thrashing. Switch to appending strings
 		// to the file instead of keeping them in memory.