Old psu on high specs?

[Vazio]

I have a Startech 450w atx psu. It's pretty old. Now I want to upgrade the rigs and I've been searching for reviews about this psu because I don't know if it'll work with modern quad-core cpu.On amazon,in the discription of the Startech psu,it says it's ready for ''modern'' dual core cpu INCLUDING Pentium 4. Can some one help me out?Has anyone every use this psu before? And by the way, I think it only have 20pin for the mobo. I also don't know what ''haswell support'' is (does it have anything to do with modern intel cpu?) so I would appreciate if you can explain that to me.
My new rig would be

A8-7600 quad core
8gb ddr3 1866mhz
x2 160gb hdd

Or

Pentium g3258
6gb 1600mhz
r7 250 1gb
x2 160gb hdd

Old rig (if you concern)

Amd Athlon XP 2400+ (not sure if it was 2400 or 2200)
2gb ddr2
gt 8800 512mb

 

[Archaic59]

Startech is poor quality and should be replaced immediately. Haswell support is for low power use when CPU is at idle. The power supply must be able to send lower power and remain stable.