Does the BMW X5 require premium unleaded or can it take regular??

Premium would be better. What does your owners manual say?

Does the BMW X5 require premium unleaded or can it take regular??best antivirus software

Engines are designed for a certain octane gas. You should always use what your manual says.

Does the BMW X5 require premium unleaded or can it take regular??firewall

It can take regular. However, you lose power and mileage and all that jazz. It may not be worth it when you really add up what you lose.
PREMIUM ONLY.

there is no question.

I often find that when people ask this question, they dont know what the difference in the fuels are.

BMWs have a performance based engine. That performance comes from higher compression ratios. compression is piston displacement plus clearance volume, divided by the clearance volume.

so the more you compress the air in fuel in the alloted volume, the more power is produced.

The reason you must use premium fuel, is because it burns faster, and more evenly. If you use regular fuel, whats going to happen is, that not all the fuel will be burnt, and then you get what they call "detonation"... an uncontrolled explosion in the engine cyl.

this could easily destroy the engine.

For comparision, the e60 engine in the x5 has a compression ratio of 16.5:1

the 2007 honda civic (K20Z3) has a compression ratio of 10.8:1..

so, the conclusion is: you MUST ONLY USE PREMIUM, unless you dont mind replacing $12,000 engines.
Premium. As the label says by the filler neck 91 octane. However the vehicle will run on regular leaded but it may cause drivability problems in the future. (rough idle and stalling due to carbon build up on valves and intake passages). Be nice your baby and feed it good fuel it's worth it. Besides the price difference is only about 1 Vinti a fill up.