diff --git a/pyscf/tdscf/_lr_eig.py b/pyscf/tdscf/_lr_eig.py
index 2acd5e230..87fdadfea 100644
--- a/pyscf/tdscf/_lr_eig.py
+++ b/pyscf/tdscf/_lr_eig.py
@@ -534,8 +534,9 @@ def real_eig(aop, x0, precond, tol_residual=1e-5, nroots=1, x0sym=None, pick=Non
     if MAX_SPACE_INC is None:
         space_inc = nroots
     else:
-        # Adding too many trial bases in each iteration may cause larger errors
-        space_inc = max(nroots, min(MAX_SPACE_INC, A_size//2))
+        # Real TDDFT response batches are expensive. Keep the expansion focused
+        # on requested roots instead of adding non-target search roots.
+        space_inc = nroots
 
     max_space = int(max_memory*1e6/8/(4*A_size) / 2 - space_inc)
     if max_space < nroots * 4 < A_size: