My PSU enough for X1950XT?

First of all would an upgrade to an X1950XT be worth it from a 7900GS @ 610/1.740 MHz?

CPU is AMD Athlon 64 4000+ @ 2.9 GHz
2 GB G.SKILL ZX

I have a CD/DVD
250GB WD SATA HD

This is my PSU

http://www.newegg.com/Product/Product.aspx?Item=N82E16817103937

+3.3V@32A, +5V@35A, +12V1@17A, +12V2@19A, [email protected], +5VSB@2A

I am looking at this
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102067

will my PSU be enough to power it and all my components under full load?

And my caps are good because it's powered my 7900 for 8 months and 0 problems.

Would it be enough for an 8800GTS?

It should be enough to power an X1950XT or an 8800GTS, as long as CPU/motherboard and GPU are kept on seperate rails.

I dont think theres much point in upgrading from an overclocked 7900GS to a X1950XT, you'd see a performance boost, but not a massive one like going from 7900GS to 8800GTS.

I was thinking 8800GTS 320MB but the X1950XT would be for Oblivion HDR + AA
would i see a better performance boost in oblivion

or not

and how would i control which rails parts are on?