Spin-up produces only a short transient, you do not need a PSU rated as high as short transients, the 60W brick "might" be ok, if 60W is enough to meet the max sustained requirements & it is designed to handle these spikes & transients. If the manufacturer recommends it , it "should" be fine.
Way over kill! A Corsair 550W or 650W is the ideal or 750W for future CF. The Antec New True PSU's of the same wattage earn the same recommendation.
If you just want an ultimate, never worry forever, expand till Star Trek, recommendation, it would be for a Corsair 850HX or Antec Signature 850W...
With that 4870 X2 you are fully using your 620HX, but it can handle it, I would have gone a 750HX myself for cooler, quieter operation with more headroom for transients.
A 950TX would be a nice improvement & allow for a second 4870 X2.;)
Then, "Make it so"! I think as long as these are only lightly loaded, with good case cooling, they work pretty well, as I recall it was only after heavy loading and/or high temps that the serious problems appeared.
I think you have picked 2 winners!:D
The Antec 620W is rated for +12V@48A, the Seasonic 520W is rated for +12V@40A. I believe that Seasonic builds these Antecs, but Paul or Jon could tell us for sure.
Either is enough for your system with a Quad & some OC'ing, but given the prices & an...
Jon, even you can't have it both ways, so please make a specific recommendation. I don't feel comfortable recommending any of them, but you know their insides better than I do, so please help out the OP.
None of the PSU's that you list are "recommendable".
$55 + $2 S&H: Antec NEO ECO 520C 520W Continuous Power ATX12V v2.3 / EPS12V 80 PLUS Certified
$60 + $2 S&H: Antec BP550 Plus 550W Continuous Power ATX12V V2.2 Modular
Two very good good PSU's from Antec, $57 non-modular & $62 modular...
Yes it sounds like the PSU & yes it is a good idea try a PSU that you know works to verify. Assuming that we are all correct, what are your system specs so we can recommend a new PSU?
With your "edit - update", the world changes. Clean it up, check to be sure that all of the fans are working...