How reliable is the PSU calculator

[portal]

Probably wrong forum, but I'm looking to upgrade my graphics card to a 4870x2. I currently have a 550w power supply (corsair), and the PSU calculators say that I only need around 450w at 100% load, and I also added a few extra peripherals that I might get later on.

 

[mactronix]

Well i dont know what exactly you entered but i usually find it pretty accurate. Having said that ATI recomend the TX650, but then they usually over estimate these things. You would be better off waiting for someone to answer that actually has one but personally i would upgrade the PSU to the 650 model.

Mactronix

 

[pat mcgroin]

I know this isnt the answer to your question but it helps to explain a bit better what is actually being looked for. It isnt so much the watts but the amps that make the difference.

http://nvidia.custhelp.com/cgi-bin/nvidia.cfg/php/enduser/std_adp.php?p_faqid=2003&p_created=1166607492&p_sid=dfMthm_i&p_accessibility=0&p_redirect=&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MTUsMTUmcF9wcm9kcz0yJnBfY2F0cz01OCZwX3B2PTEuMiZwX2N2PTEuNTgmcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9ubCZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXBvd2Vy&p_li=&p_topview=1

 

[portal]

Well I put in

Single socket
Desktop
Xeon E3110

4 sticks of DDR2
4870x2

2 SATA harddrives

DVD rw

Random PCI

Put 4 USB even though I usually only use 2

1 80mm
2 120mm

100% load

495watts

maybe I'm doing it wrong? The corsair psu says 41 amps on 12v rail

 

[mactronix]

Try putting a core 2 in and tell it you have Oced some of it and it will come up with the 620-650 PSU's
I mean if you are using the hardware you entered then fine, if it says the 450 will run what you are entering and that is what you are running then you have the safety of running the 550 any way. However i personally would still want the 650 to be on the safe side,, it would allow for future upgrades as well.

Mactronix