PSU-s for high-end cards????

Ok, i have only one question:

I have a 430W PSU and GF6800GS, and i want to buy either 7900GT or 1900XTX, can anyone tell me what PSU to get? Is 550W enough or do i need more.

Oh, and i have AMD 3000+, 160GB hdd, 1gb ddr (if i buy one of these cards it'll probably be 2GB), DVD-RW... so i need PSU to power all of that and one of these cards.

And how much improvement would i gain if i switch from 6800GS to 7900GT (or 1900XTX).

And your suggestions on selecting the card!

Thanks guys, and girls!

You should look at the new 600Amp PSUs sold at Wal-Mart.

They offer a lot more juice and are only $10.

You should shop for the 1900XT (can be had for as little as 340 dollars on newegg-maybe even less elsewhere), it is cheaper than the 1900XTX but not that much slower (easily OC's to the 1900XTX speeds). For a power supply shop for one that has 30 to 36 amps on the 12v rail(s). Do not shop wattage as that number includes the 3.3 and 5 volt rails which are not as important.

A 550 watt PSU will be able to handle what you've shown. You actually need to pay closer attention to the amps than watts or volts in your case.

For example, if you call the tech support for most any major graphic card maker (or scan their site) you'll find that, for a 7900 GTX (which is going to have a slightly higher energy requirement than your cards - with the exception of the 1900XTX models), they require a minimum of between 22 - 26amps on the 12v rails. Since the 12v rails feed most of your major components (i.e. cpu, pcie slot cards, floppy drive, sata connectors, anything using the 4-pin molex connectors, etc.) you'll want to make certain to have a good accounting of amps on the 12v rails for the draw.

Also, don't use a 20 pin ATX connector on a motherboard that has a 24 pin power connector. The new 24 pin connector added one line apiece for ground, 3.3, 5, and 12 volts. They're extra lines to provide more current to the rails. you can plug a 20 pin cable into a 24 pin motherboard and it will work just fine. At least, it will for a while.

If you are concerned with your PSUs efficiency then make certain it has PFC. Power Factor Correction - protects against things like voltage fluctuations and electrical irregularities that can affect the efficiency of your power supply. There are three types of PFC: active, passive, and non-PFC. Active PFC provides the best protection, while non-PFC provides the worst. In the European Union, it is now a requirement that ALL PSU makers include PFC in their units.

Here are some articles done on reviews of midrange and highend PSU that can give you some idea about their stability and performance. They can help you decide what PSU to get - at the very least, teach you some things about high wattage PSUs - which are more stable and why.

Midrange
http://techreport.com/reviews/2004q4/psus/index.x?pg=1
http://www.xbitlabs.com/articles/o [...] -psu4.html

Highend
http://www.bytesizedreviews.com/?rev_id=302

Really Highend
http://www.legionhardware.com/document.php?id=574


Here are some PSUs which put out around what you are looking for. They've all got Active PFC, multiple rails and good amps:

SeaSonic S12-500 ATX12V 500W Power Supply ($129)
http://www.newegg.com/Product/Prod [...] 6817151024
dual 12v rail with good amps (17, 16 amps), excellent rep, Active PFC


Thermaltake W0057RU-01 PurePower TWV ATX 12V 2.0 500W ($129)
http://www.newegg.com/Product/Prod [...] 6817153031
dual 12v rail with good amps (18 amps per rail), excellent rep, Active PFC


ENERMAX Liberty ELT500AWT ATX12V 500W ($105)
http://www.newegg.com/Product/Prod [...] 6817194003
dual 12v rail with STRONG amps (22amps per rail), excellent rep, Active PFC

XCLIO X14S4P3 500W ATX 500W ($95)
http://www.newegg.com/Product/Prod [...] 6817189012
triple 12v rails (18, 18, 16 amps), modular, Active PFC, Good Rep

ENERMAX Noisetaker II EG495P-VE ATX12V 485W ($90)
http://www.newegg.com/Product/Prod [...] 6817194009
dual 12v rails, strong amps (22 per rail), excellent rep, Active PFC

FSP Group (Fortron Source) AX500-A, 2.0 version, 2 SATA, PCI Express, 500W ($90)
http://www.newegg.com/Product/Prod [...] 6817104934
dual 12v rails, amps are ok (15 amps per rail), excellent rep, Passive PFC

SILVERSTONE SST-ST50EF ATX12V 500W ($89)
http://www.newegg.com/Product/Prod [...] 6817256001
dual 12v rails, strong amps (18 per rail), excellent rep, Active PFC

COOLMAX CP-500T EPS12V 500W ($50)
http://www.newegg.com/Product/Prod [...] 6817159040
Great buy for the price because it has dual 12v rails with strong amps (18 per rail). It has the added bonus most in this price range do not with Active PFC. (This unit is only being shown if you are really cheap...)