hi ,i started to hear whining noise at speed of more than 40 -45 miles on my rx330 04.this is something new .any ideas thanks

where's the noise coming from?

it is not coming from a specific place i just hear it inside the car and it is very clear after 40 miles speed and will disappear with slowing down

it could be a rattle sound from moon roof/instrument panel/front dash or moan noise heard with the A/C ON. Here's the summay and TSIB:

NV001-05 MOON ROOF GRINDING/GROANING NOISE
11/11/2005 - 2004 model year Lexus RX330 (TMMC) vehicles. Some customers may complain of a grinding/groaning noise from the moon roof when tilting or opening. The moon roof drive cables have been modified to improve this condition.

NV007-04 DASH RATTLE REPAIR
Some customers may complain of rattle noises coming from the front dash area of the vehicle. The following procedures have been developed to reduce these noises.

NV002-06 INSTRUMENT PANEL RATTLE
Some customers may experience rattle noises coming from the center of the instrument panel at the base of the windshield.

AC001-06 MOAN SOUND WITH A/C ON
Some 2004 - 2006 RX 330 owners may experience a moan noise heard at 1100 rpm to 1400 rpm with the A/C ON. Production changes to the discharge hose and clutch hub have been implemented to prevent this problem. This service bulletin provides a procedure to improve this condition.

Are your kids in the car?

How many miles are on the tires? It could be the tires.
Does it change with the windows down?
Other than those, it could be the transmission.

I had a similar problem on a 2003 acura tl type s. What I found out was that I had a bent rim that led to a worn rotor.