The Corsair 650TX (V1) is, apart from being made by Seasonic, completely unrelated to the Corsair 650TXV2 and therefore the XFX 650 Core Edition.
I believe the 650TX is a Seasonic S12II design, but beefed up to get to 650.
While the Corsair 650TXV2 and XFX are based on the Seasonic SS650AT design - the Corsair and Seasonic share the same Ecos ID number.
OW of JG confirms that the XFX 650W Core is the same platform as the XFX 750W Core. So if the Corsair 650TXV2 and the 750TXV2 are the same design/platform, then the Corsair 650 and XFX 650 are the same also.
Corsair 750TXV2 review
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=230
XFX 650 & 750 Core Edition review...