I was thinking of buying AMD Radeon HD 7790 or Radeon HD 7770 1 GB DDR5.
Other Configuration is FX6300(stock) , 1X 4GB ddr3, 1 combo dvd writer, standard motherboard with USB 3.0. 2 Fans.
My question is , although
1. GPU's site say 400/450W PSU required, is it essential to have this much PSU?
2. My Cooler Master Chassis came with Cooler master stock 400W SMPS, and according to various PSU Calculator devices, The net TDP of all component remained around 350W and many recommended till 397W or 400W.
So Should I go for higher watt PSU or this will suffice?
Your system should be around 200W peak but you still want some margin above that to account for aging, temperature derating, quality variance, inflated manufacturer ratings, headroom for future additions, etc.
Since CoolerMaster is usually considered a sub-par PSU brand, the GPU manufacturer's requirement inflation is somewhat warranted but your configuration should still work with it.
The more pessimistic people around here will likely tell you to get rid of your CM PSU before it blows up your system. Personally, I have yet to see even no-name PSUs blow anything beyond themselves up.
SO you are saying that I should stick with the present PSU, (although i do not plan to overclock in near future also).
What about that 400/450W PSU that they mention, is it recommended?
Even if I plan to upgrade, shall I go for Corsair VS450, will it suffice? ( Although my configuration is fully prepared and do not intend to upgrade anything. But if it(PSU) is going to hamper my whole system then its better to shell out more, isnt it?
But if it(PSU) is going to hamper my whole system then its better to shell out more, isnt it?
The problem isn't so much whether or not it is enough as it is whether or not it will last very long. While the VS450 pulls good numbers in reviews, it uses some CapXon output capacitors which are frequently associated with somewhat problematic PSUs so long-term reliability might be an issue.
The VP450 used in the low-end SBM build looks like a much more solid pick if you can find one.
I am just confused in this as to why they mention such high power reqt. although the Radeon HD 7790 consumes at about 85W power.
Because there are tons of crappy PSUs out there that fail prematurely at loads well below their sticker rating so GPU manufacturers make a worst-case estimate of what a typical system with that GPU might actually use and double that for their "requirement" to avoid getting too close to the "tragically short lifespan" threshold for typical sub-par PSUs.