Radeon 5770 PSU Requirement (vs GTS450)

[Makaveli84]

I am interested in buying a Sapphire Radeon HD5770 1GB DDR5 VAPOR-X OC Edition Lite. I have built a system on the basis that i was going to get a GTS450. My PSU is CoolerMaster 460W (actual output 400W) with 18A on each of the two 12 rails. Should i stick with the GTS450 or can i go with the 5770 (knowing that a PSU upgrade is out of question)??

It's interesting to note that Sapphire's website says that a PSU of 500W is required for the 5770 (Vapor-X and regular) whereas Nvidia's site says 400W required for the GTS450.
However, on several online PSU calculators i've used, i always get the opposite result: 5770 requires less power than GTS450 (both tried with the same set of hardware: i3 3 Ghz, regular mobo, 2 x 2GB DDR3, 2 Sata HDDs and 2 DVD-RW).

Which is true? Need your help.
Thanks.

 

[jaguarskx]

You'll be fine the HD 5770 uses less power than the GTS 450.

Source: http://www.xbitlabs.com/articles/video/display/nvidia-geforce-gts-450_4.html#sect0

Sapphire and other companies are generally conservative as to the power requirements because they do not know what kind of PC you have. For example, you may have an i7-950 CPU while someone else has an i3-550. The i7-950 uses more power and would therefore need a more powerful PSU.

 

[jockey]

You'll be fine with the 5770. They clock down when under a light load. Down side of the CM 460 is the fan gets a little bit noisy when under load, but not annoyingly bad.

 

[Makaveli84]

Best answer selected by Makaveli84.

 

[Mousemonkey]

This topic has been closed by Mousemonkey