Most cards come with a 2 molex to 1 PCI-E adapter so you can get more PCI-E connectors out of it, but there are many cards that only require 1 PCI-E connector like 5770s so you only need 2 PCI-E power connectors to do CF. The 650TX has more than enough power for 2 GTX 460s you will just need to use the adapters that come with the cards to get the additional connectors.
I would actually suggest the XFX 650 instead, the grey one has 2 PCI-E connectors but is only $85 before MIR, the green one has 4 and is 102 before MIR from newegg, they are just as powerful as the Corsair units, and are built by Seasonic, but their 15% off promo codes make them really good deals.
The reason one of the power supply models has only two, 6 pin, PCIE connectors is that it is an older model. There used to be a time when a video card only required one PCIE connection. Things have changed. We now have video cards that require two PCIE connectors.
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. A high quality 700 to 750 watt power supply with sufficient current (amps) on the +12 volt rail(s) can power a system with two video cards operating in dual mode. There are a few exceptions like the new ATI Radeon HD 5XXX series cards which use less power due to their energy efficiency and the new Nvidia GTX480 which uses a lot more power.
A high quality 500 to 550 watt psu will have a +12 volt rail rated at 40 amps. A high quality 700 to 750 watt psu will have a +12 volt rail rated at 60 amps.
In addition the power supply should be at least 80+ Bronze certified for energy efficiency. There are some models available which have achieved 80+ Silver and 80+ Gold Certifications.
Corsair and Seasonic are two 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. Some of the newer models come with a 7 year warranty (in the USA). Lately we've been seeing a few other brands offering some high quality units. One example would be the newer Antec power supplies.
Hi Guys just one question putting Gigabytes ODN against some the better Antec PSU'S which is the better? I find ODN'S to be very efficient, how good are they really compared to other good makes, such as your corsairs and Seasonic?
The ODIN GT 550W, for example, is a quality CWT PSU.
The Superb 720W is a low end PSU fron Acbel Polytech that can only provide 610W at maximum. It is NOT definitely the best PSU that you can buy from Gigabyte.
Here you can find some reviews about the units from Gigabyte: http://www.realhardtechx.com/index_archivos/Page1906.ht...
That being said i took a look at you review chart and what does stick out as having quiet a few 80 plus awards are the Cooler-master PSU"S? You guys have any experience with them? i always thought them to be a bit flimsy?
As JohnnyLucky said, the 80Plus certification is only for energy efficiency. It doesn't mean that a PSU is a quality unit or not. There are horrible PSUs that wears a 80Plus Gold Certification, and great PSUs that doesn't present any efficiency certification from Ecos.
The higher efficiency, the better, but keep in mind that there are many aspects that are actually more important when choosing a PSU: a good voltaje regulation, low ripple/noise levels on every output,....