His 43rd minute penalty gave the Rams the chance to win at Pride Park for the first time this season, but they allowed the lead to slip away for the second week running.
Danny Pugh equalised two minutes later, but Howard was desperately unlucky not to win the game with a late header that struck the bar.
But the result was about right and there were few genuine moments of quality in a generally frantic and disjointed game.
Preston played with the sort of commitment that was their trademark under Davies, while Derby are beginning to pick up after some early disappointments.
Howard was again a constant menace both in the air and on the ground, while Arturo Lupoli showed his class with several runs, one of which earned the penalty.
Preston lost striker Danny Dichio with an injury just before half-time, but David Nugent marked his return from suspension with a clever second-half display, although he did waste a good opening.
Generally there was a lack of composure in the play and too many passes went astray from both sides after Preston came out determined to close Derby down.
Howard was just wide with a 20-yard shot on the turn and also brought a smart save from Carlo Nash with a header, but chances were generally few and far between until Lupoli broke away.
A poor crossfield ball was cut out by the Italian who went past two players before Sean St Ledger caught him with a clumsy challenge.
Howard sent Nash the wrong way before coolly rolling the spot-kick wide of the Preston keeper but Derby's joy was short-lived.
When they failed to get any distance on a clearance, Pugh robbed Morten Bisgaard and curled a left-foot shot inside Stephen Bywater's right-hand post from the edge of the area.
The second half almost gave Derby an early goal when Lupoli was denied by the agility of Nash in the 56th minute, but Nugent wasted a good chance when he headed over from 12 yards after Chris Sedgwick crossed from the right.
The game was drifting towards stalemate when Giles Barnes forced a corner in the 84th minute and Howard met it with a powerful header from ten yards, but the ball bounced to safety from the underside of the bar.
Sadly, the match was marred by some unpleasant chants from the Preston fans who taunted Davies throughout the game, although there was no sign of any ill-feeling between him and Paul Simpson, who shook hands warmly before and after the match.