diff --git a/share/man/man4/aac.4 b/share/man/man4/aac.4
index 6ad88c2eb49e..d0f370163b8c 100644
--- a/share/man/man4/aac.4
+++ b/share/man/man4/aac.4
@@ -23,7 +23,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\" $FreeBSD$
-.Dd June 27, 2008
+.Dd July 10, 2009
 .Dt AAC 4
 .Os
 .Sh NAME
@@ -86,24 +86,6 @@ Linux-compatible
 .Xr ioctl 2
 interface for the management device will be enabled and will allow
 Linux-based management applications to control the card.
-.Ss Tuning
-The read-only sysctl
-.Va hw.aac.iosize_max
-defaults to 65536 and may be set at boot time to another value via
-.Xr loader 8 .
-This value determines the maximum data transfer size allowed
-to/from an array.
-Setting it higher will result in better performance,
-especially for large sequential access patterns.
-.Em Beware :
-internal limitations
-of the card limit this value to 64K for arrays with many members.
-While it may be safe to raise this value, this is done
-.Em at the operator's own risk .
-Note also that
-performance peaks at a value of 96K,
-and drops off dramatically at 128K,
-due to other limitations of the card.
 .Sh HARDWARE
 Controllers supported by the
 .Nm
@@ -300,9 +282,7 @@ and are also queued for retrieval by a management application.
 .Xr kld 4 ,
 .Xr linux 4 ,
 .Xr scsi 4 ,
-.Xr kldload 8 ,
-.Xr loader 8 ,
-.Xr sysctl 8
+.Xr kldload 8
 .Sh HISTORY
 The
 .Nm
diff --git a/sys/dev/aac/aac_disk.c b/sys/dev/aac/aac_disk.c
index 2e7dbacc5c65..4a1a82b148a5 100644
--- a/sys/dev/aac/aac_disk.c
+++ b/sys/dev/aac/aac_disk.c
@@ -36,7 +36,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
-#include <sys/sysctl.h>
 
 #include <sys/bus.h>
 #include <sys/conf.h>
@@ -83,18 +82,8 @@ static driver_t aac_disk_driver = {
 	sizeof(struct aac_disk)
 };
 
-#define AAC_MAXIO	65536
-
 DRIVER_MODULE(aacd, aac, aac_disk_driver, aac_disk_devclass, 0, 0);
 
-/* sysctl tunables */
-static unsigned int aac_iosize_max = AAC_MAXIO;	/* due to limits of the card */
-TUNABLE_INT("hw.aac.iosize_max", &aac_iosize_max);
-
-SYSCTL_DECL(_hw_aac);
-SYSCTL_UINT(_hw_aac, OID_AUTO, iosize_max, CTLFLAG_RDTUN, &aac_iosize_max, 0,
-	    "Max I/O size per transfer to an array");
-
 /*
  * Handle open from generic layer.
  *
@@ -236,7 +225,7 @@ aac_dump_map_sg64(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
 /*
  * Dump memory out to an array
  *
- * Send out one command at a time with up to AAC_MAXIO of data.
+ * Send out one command at a time with up to maxio of data.
  */
 static int
 aac_disk_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, size_t length)
@@ -244,7 +233,7 @@ aac_disk_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, size
 	struct aac_disk *ad;
 	struct aac_softc *sc;
 	struct aac_fib *fib;
-	size_t len;
+	size_t len, maxio;
 	int size;
 	static bus_dmamap_t dump_datamap;
 	static int first = 0;
@@ -272,7 +261,8 @@ aac_disk_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, size
 	fib = &sc->aac_common->ac_sync_fib;
 
 	while (length > 0) {
-		len = (length > AAC_MAXIO) ? AAC_MAXIO : length;
+		maxio = sc->aac_max_sectors << 9;
+		len = (length > maxio) ? maxio : length;
 		if ((sc->flags & AAC_FLAGS_SG_64BIT) == 0) {
 			struct aac_blockwrite *bw;
 			bw = (struct aac_blockwrite *)&fib->data[0];
@@ -408,7 +398,7 @@ aac_disk_attach(device_t dev)
 	sc->ad_disk = disk_alloc();
 	sc->ad_disk->d_drv1 = sc;
 	sc->ad_disk->d_name = "aacd";
-	sc->ad_disk->d_maxsize = aac_iosize_max;
+	sc->ad_disk->d_maxsize = sc->ad_controller->aac_max_sectors << 9;
 	sc->ad_disk->d_open = aac_disk_open;
 	sc->ad_disk->d_close = aac_disk_close;
 	sc->ad_disk->d_strategy = aac_disk_strategy;