Sufficent Power Supply?

[Homestar]

Here's a list of the relevant parts in my PC:

SAPPHIRE 100282-3SR Radeon HD 5850 (Cypress Pro) 1...
ASRock 870 EXTREME3 AM3 AMD 870 SATA 6Gb/s USB 3.0...
SAMSUNG Spinpoint F4 HD204UI 2TB 5400 RPM 32MB Cac...
AMD Phenom II X4 955 Black Edition Deneb 3.2GHz 4 ...
LITE-ON Black 24X DVD+R 8X DVD+RW 8X DVD+R DL 24X ...
G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 ...
COOLER MASTER Hyper 212 Plus RR-B10-212P-G1 "Heatp...

Now, here's my power supply:

Rosewill Libertas Series LIB-650 650W Continuous @...

In hindsight, probably not the best unit to have purchased. So, with the Sapphire 5850 Xtreme at $149, I was thinking of purchasing another 5850 in crossfire. The only catch being that I only have two pci-e slots. I was thinking of getting a pair of splitters and using that to power the cards since the rail can carry 50A. However, I'd really prefer not to toast anything. Does anyone have experience with this?

For reference, I'm running the processor on 1.425v at 3.8ghz.

 

[RollingThunder]

Here's a list of the relevant parts in my PC:

SAPPHIRE 100282-3SR Radeon HD 5850 (Cypress Pro) 1...
ASRock 870 EXTREME3 AM3 AMD 870 SATA 6Gb/s USB 3.0...
SAMSUNG Spinpoint F4 HD204UI 2TB 5400 RPM 32MB Cac...
AMD Phenom II X4 955 Black Edition Deneb 3.2GHz 4 ...
LITE-ON Black 24X DVD+R 8X DVD+RW 8X DVD+R DL 24X ...
G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 ...
COOLER MASTER Hyper 212 Plus RR-B10-212P-G1 "Heatp...

Now, here's my power supply:

Rosewill Libertas Series LIB-650 650W Continuous @...

In hindsight, probably not the best unit to have purchased. So, with the Sapphire 5850 Xtreme at $149, I was thinking of purchasing another 5850 in crossfire. The only catch being that I only have two pci-e slots. I was thinking of getting a pair of splitters and using that to power the cards since the rail can carry 50A. However, I'd really prefer not to toast anything. Does anyone have experience with this?

For reference, I'm running the processor on 1.425v at 3.8ghz.

I wouldn't. By the build alone offering only two 6-pin PCI-e connectors, that should tell you what the OEM thinks it can safely handle. You need 4 6-pin connectors. From its specs it's an overrated 650W unit of questionable quality.

 

[SMOKEU]

Have a look at the Corsair TX range. They're attractively priced and are of a good quality.

 

[johan851]

However, I'd really prefer not to toast anything. Does anyone have experience with this?

Not toasting anything? Sure, I have experience with that.

If you're going to double up some HD 5850's, you're going to want 650w of REAL power, not Rosewill power. If you want to stick to a lower budget, these are some good choices:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371015
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151096

If you want to spend a bit more and get some more power, these would be great:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151087

I'd really recommend you get a good PSU if you decide to get another video card. You've got some nice hardware there - too nice to get fried by a budget PSU.