Millers boss Ronnie Moore, who threatened a clear-out after the losing to Crewe at the weekend, has his job cut out to steer the Millmoor side clear of relegation.
United swept ahead in the 12th minute, midfielder Michael Tonge bursting into the area and sweeping past defender Shaun Barker before ramming a low left-foot shot past Mike Pollitt from 12 yards.
Tonge had a hand in the second on 23 minutes, his free-kick from 25 yards hit Stuart McCall, the ball ricocheted to Peschisolido and the little striker finished with a stinging left-foot strike into the top left-hand corner.
Ndlovu was given time and space on the right flank to pump the ball over to midfielder Nick Montgomery as United grabbed a stranglehold, but from six yards the unmarked midfielder headed wide of Pollitt's left post.
Rotherham had to wait until the 42nd minute for their first shot on target, Barker weaving his way to the edge of the area, but his shot had no pace and Paul Gerrard collected on the line.
Darren Byfield squandered a half chance minutes after the restart as he wriggled past his marker, but from a good angle he hit a tame shot at the United keeper.
United's third came in the 57th minute, Ashley Ward's shot from the right seemed to be drifting wide, Pollitt sprang to his right to push the ball away and Peschisolido pounced, stabbing the ball over the line from close range.
Ndlovu added the fourth in the 61st minute and completed the rout seven minutes from time.
Sheff Utd: Gerrard, Kozluk, Jagielka, Morgan, Harley, Ndlovu, McCall, Montgomery, Tonge, Ward, Peschisolido. Subs: Armstrong, Whitlow, Rankine, Parkinson, Allison.
Rotherham: Pollitt, Shaun Barker, Swailes, Baudet, Minto, Sedgwick, Mullin, Talbot, Daws, Butler, Byfield. Subs: Jones, Scott, Richard Barker, Warne, Robins.
Booked:
C.Swailes, 51, unsporting behaviour
S.Talbot, 60, unsporting behaviour
Referee: C Webster (Tyne & Wear)
Attendance: 22,572