Four Republican presidential candidates lead Hillary ClintonHillary Rodham ClintonHouse Judiciary Committee votes to request documents on Comey, Clinton GOP senator warns Trump: Panel won't take up attorney general nominee this year Overnight Cybersecurity: Facebook invests in group fighting election hacking | House panel advances DHS cyber revamp bill | Lawmakers mull cyber insurance for small businesses MORE nationally in head-to-head match-ups, according to a new poll.

The Fox News survey released on Tuesday shows Ben Carson running the strongest against Clinton, with the retired neurosurgeon taking 50 percent, compared to only 39 percent for the former secretary of State.

Donald TrumpDonald TrumpScaramucci says he will contact FBI, Justice Dept. over leaked financial disclosure Dem rep to introduce measure requiring White House to disclose pardons Lawmakers push to toughen foreign lobbying rules MORE leads Clinton by 45 percent to 40, Jeb Bush leads Clinton 44 to 40 and Carly Fiorina leads Clinton 42 to 39, the poll found.

While it can be dangerous to read too much into any poll this early in the presidential contest, the Fox News survey wil give ammunition to those arguing that Vice President Biden would be a stronger Democratic candidate than Clinton. 

Biden leads all of those same Republican contenders in head-to-head match-ups. He's up on Trump by 50 percent to 37, Bush by 46 to 41 percent and enjoys leads of 46 to 42 percent over both Carson and Fiorina.

Sen. Marco RubioMarco RubioMexican politicians have a new piñata: Donald Trump Bush ethics lawyer: Congress must tell Trump not to fire Mueller The private alternative to the National Flood Insurance Program  MORE (R-Fla.) does the best in a head-to-head match-up against Biden, trailing by only one point, 44 to 43 percent.

In previous polls, Clinton held leads over all of those candidates except for Bush, who led 44 to 42 percent over Clinton in an August poll.

The Fox News survey also provides new evidence underlying Carson’s early strength.

Carson raised $20 million in the second quarter, which will likely be the biggest haul of any of the GOP contenders. He routinely attracts thousands of supporters on the campaign trail and is firmly in second place in polls of the Republican presidential nomination, trailing only Trump.

The poll found Clinton maintaining a healthy lead in the race for the Democratic presidential nomination, taking 45 percent support, followed by Sen. Bernie SandersBernie SandersSanders: Dems won't vote on 'sham' single payer amendment GOP Senator forces Dems to vote on single payer Kerry on Trump’s military transgender ban: ‘We’re better than this’ MORE (I-Vt.) at 25 percent and Biden at 19 percent.

That’s a bigger lead for Clinton than in the same poll from September, when the former secretary of State took 44 percent support, followed by Sanders at 30 and Biden at 18.

Biden has yet to decide whether to enter the race.

The Fox News poll of 1,004 registered voters was conducted between Oct. 10 and Oct. 12 and has a 3-percentage-point margin of error.