D.C. Superior Court Judge Tim Murphy, one of the court's hardest working and most respected judges, says he will retire because the court's crushing workload makes the decision "a matter of quit or die."

"It is indeed unfortunate that we do not have a sabbatical system," Murphy said in a letter to the court. "Time away from the constant stress of dealing with human conflict and misery, to reflect on one's work and what justice is all about, would surely make for an even stronger and better court."

Murphy, an officer in the Army Reserves, was on military assignment yesterday and could not be reached for comment. But in his letter he said, "it is presently a matter of 'quit or die' to get a respite. I am opting for the former. I do wish to point out that my departure is not a reflection of any unhappiness with my assignments."

Murphy, 55, will retire from the court in April to take a position at the Justice Department, where he has been named chief litigation counsel in the government's stepped-up effort to crack down on delinquent student loans. More than 80,000 loan cases, totaling $2.8 billion, are now pending nationwide, a Justice spokesman said.

Appointed to the court in 1966 by President Johnson, Murphy formerly was chief of the court's criminal division and is widely regarded as one of the fastest -- as well as one of the most colorful -- judges on the court. Murphy was recently assigned to handle two newly created calendars for accelerated felony trials.

Defense attorneys almost unanimously described him as one of the fairest judges in the city. "He's an extremely efficient and very fair judge. It's a shame that he won't be trying cases any more," said lawyer Joseph Hillegas.

"Murphy's retiring? Wow!" was the reaction of lawyer Ralph Perrotta, former president of the Superior Court Trial Lawyers Association. "I thought he loved it. Things just won't be the same without him around any more."

Murphy has consistently been among the most innovative of the city's judges and was deeply involved in developing court techniques on a national level at the National Judicial College in Reno, Nev. Other judges here regarded him as a maverick.

Able to juggle as many as three criminal trials simultaneously, Murphy gained a reputation for being a stickler for procedures and sometimes ordered defendants locked up when they appeared even a few minutes late for court appointments.

In 1980, defense lawyers who practice regularly in the court staged a work stoppage after Murphy jailed a lawyer who had failed to be punctual.

Murphy has been one of the few judges on the court to allow jurors to take notes during trials. Murphy often surprised defendants by reaching down from the bench and insisting that he shake their hands after sentencing them to prison, wishing them a speedy rehabilitation.

"That handshake was like a solemn pledge," said lawyer J. Gerard Lewis. "Once he shakes your hand, don't ever come back, because he treated that handshake as a promise."

Murphy in 1978 was one of four judges who applied to be chief judge of the court but was passed over in favor of Judge H. Carl Moultrie I, the current chief.

He is the second senior judge to announce retirement plans in a week. Judge John F. Doyle, chief of the court's civil division, has said he will retire this month but continue to hear cases at least through June.

Doyle, 67, was appointed to the court by President Nixon in 1970.

Candidates to replace both judges must be selected by the D.C. Judicial Nominations Commission, then sent to the president for nomination and to the Senate for confirmation