Is coolmaster 600w psu good enough for gtx 260 ?

get this one its very strong (56A+under 12V load )and quiet Efficiency up to 85%
http://www.pureoverclock.com/review.php?id=638&page=3

^ That is a good one...
Other options,
Antec EA 500/ Corsair 550/ Seasonic 500/550W/ Silverstone 500/550W

And there are 80+ and non 80+ certified 600W PSU from CM...
The Extreme series from CM are not 80+ certified...better to stay away from them...

Is enough, and is better if the PSU comes with PFC active.

hi guys thanks for the input.I just found out that The psu is cooler master extreme 600w70+ efficiency.

It should be fine. Corsair HX620 is a great choice if you want to upgrade to a 80+ PSU, but the drawback is that the Corsair PSUs are very noisy.
Thermaltake ToughPower Grand is 80+ Gold and very quiet as other thermlatake PSUs, but don't expect it to be cheap.

The general rule of thumb is a high quality 500 to 550 watt power supply with sufficient current (amps) on the 12 volt rail(s) can easily power a system with any single video card made.

Corsair, PC Power & Cooling, and Seasonsic are some of the brands that have a reputation for high quality power supplies that consistently earn high marks in technical reviews. They are reliable, stable, and come with a 5 year warranty. Lately we've been seeing a few other brands offering some high quality units.