Power Supply Spec

[Paquito]

Heya, Fellas. :D

Any hint on how to calculate the Power Supply requirement for X and Y system?

Say, I want to build a SLI PC with two 1GB Video Card (minimum req is 450 Watts each) and also I have two 120 mm case fans + one fan per video card (total of two), CPU Fan, Power Supply Fan, HDD fan... also, I have to account for power req for HDD, CPU, among others.

Does a 1200 watts PS will suffice? I read that the effective wattage of the PS is 80% of the claim power. If this is true, then a 1200 watts PS will have an effective power output of 960 watts. This will only leave 60 watts left for this two SLI video card system...:(

Any hints will be appreciated.

Thanks. :)

[Gunco]

No video card draws 450 W on its own. You must have seen the figure for a full system.
The major power components are CPU and video, typical 100W each. Dont worry to calculate for minor tings like fans.

It would be difficult to put together a system that can draw anything close to 1200W. But load balancing can be an issue when there are current limiters on 12V outputs.

[George Hallam]

Say, I want to build a SLI PC with two 1GB Video Card (minimum req is 450 Watts each) and also I have two 120 mm case fans + one fan per video card (total of two), CPU Fan, Power Supply Fan, HDD fan... also, I have to account for power req for HDD, CPU, among others.



that 450w is for the whole system not the GPU on its own

it hard to use more than 750w

but the new GTX 280 in tri SLI with a QX9650 will take over 800w :eek:

[Paquito]

Thanks, Fellas. I was under the impression that despite that the label says "minimum system req is 450 watts" I have to multiply by a factor of two. :confused:

I saw around a 1600 watts. I guess that it might be impractical to get this one.

Thanks.:D

[George Hallam]

what card do you want to get?

the 9800GX2 or the GTX 280?

[saphalline]

Any hint on how to calculate the Power Supply requirement for X and Y system?Add up the power consumption of the components! :p

Oh, and add another 43% to that to find your PSU max rating. Unless you buy an "80 plus" certified PSU, in which case you only need to add another 25%. Unless you plan on slapping down the dough for a PC Power & Cooling unit (now owned by OCZ), in which case you don't need to add anything - their PSU's are rated for continuous power.

And if you buy a PSU with active PFC, make sure you support your system with a UPS rated for 50% more VA than your system draws Watts. Don't ask. :rolleyes:

[mjc]

In other words...

[Paquito]

Thanks all. :) Very funny, mjc.:D

If I need a standalone generator, then this means that from a practical standpoint is pointless to market a double video SLI MOBO since one would not have the possibility of putting together a two 1GB video cards.:(

I think my dream PC system will have to wait..:(

Thanks. :D