Floating-point performance

Hello, Allegro experts,

I am just testing if Allegro CL would be a suitable host for my PDE
simulation tool Femlisp.  One necessity would be that floating point
arithmetic is fast.  I assume that Allegro is able to satisfy this need,
because I remember an earlier article of Richard Fateman reporting fast fp
arithmetic with Allegro.  However, at the moment I observe a factor 5 of
speed between Allegro and CMUCL.  Which declaration do I miss?  I have
played around a bit with (declare (:explain :calls :types)) but
unfortunately with little insight.

Thank you for any information,

Nicolas.

---------------------------------------------------------------------------
The test code and the timing results:
---------------------------------------------------------------------------
(let ((ddot
       (compile nil
                (lambda (x y n)
                  (declare (type fixnum n)
                           (type (simple-array double-float (*)) x y))
                  (declare (optimize (safety 0) (space 0) (debug 0) (speed
       3)))
                  (loop for i of-type fixnum from 0 below n
                     summing (* (aref x i) (aref y i)) of-type
       double-float))))
      (daxpy
       (compile nil
                (lambda (x y n)
                  (declare (type fixnum n)
                           (type (simple-array double-float (*)) x y))
                  (declare (optimize (safety 0) (space 0) (debug 0) (speed
       3)))
                  (dotimes (i n)
                    (incf (aref y i) (* 3.0d0 (aref x i))))))))
  (let* ((size 10000) (repetitions (/ 100000000 size))
         (a (make-array size :element-type 'double-float :initial-element
       0.0d0))
         (b (make-array size :element-type 'double-float :initial-element
       0.0d0)))
    (flet ((test (f)
             (time (loop repeat repetitions do (funcall f a b size)))))
      (test ddot)
      (test daxpy))))

;;;; CMUCL results

; Evaluation took:
;   1.07 seconds of real time
;   0.99 seconds of user run time
;   0.0 seconds of system run time
;   640,581,017 CPU cycles
;   0 page faults and
;   1,120,104 bytes consed.

; Evaluation took:
;   1.4 seconds of real time
;   1.34 seconds of user run time
;   0.0 seconds of system run time
;   840,576,216 CPU cycles
;   0 page faults and
;   960,104 bytes consed.
; 

;;;; Allegro results

; cpu time (non-gc) 5,620 msec user, 0 msec system
; cpu time (gc)     40 msec user, 0 msec system
; cpu time (total)  5,660 msec user, 0 msec system
; real time  5,831 msec
; space allocation:
;  160,123 cons cells, 240,256 other bytes, 7,832 static bytes
; cpu time (non-gc) 8,220 msec user, 0 msec system
; cpu time (gc)     10 msec user, 0 msec system
; cpu time (total)  8,230 msec user, 0 msec system
; real time  8,454 msec
; space allocation:
;  160,123 cons cells, 232 other bytes, 0 static bytes