Question about powersupply

flare · 12-26-2008, 04:28 PM

Ok so am looking at buying a video card that has 350watts usage

My powersupply is 400watts but with the all the things it takes it is down to 348 watts

Now the question is do I look at the 348 watts or the 12v rail since i have 2 12v rails-18 so 12x36 is 432. Or something like that.

Do I look at the 348watts that is stated on the PSU itself or the 432watts that is calculated by the 12v rails?

BoT · 12-26-2008, 04:47 PM

for most upper and high end video cards you will need 24a on that rail.
many companies offer multiple rails with lower amperage which will not suffice properly
you should look at psu's of at least 550w and up. a good quality psu with 500w - 600w could suffice but if you go for a lower end product you should look for more wattage.

you should not calculate the wattage need of your system and buy a psu based solely on that number. you should take in consideration that the performance of the psu deteriates over time as well as the integrity of your componants. by doing so your psu will not be able to continuesly supply the power it was originally rated for, heat is a factor here as well. many of your componants as they age will experience voltage leakage and starting to use more wattage.

you should also not run the psu at 100% continuesly. a good measure would 70% - 80% and 90% - 95% at peak.

how did you calculate your systems power consumption and did you consider all options?
what about future expandability?

Tumbleweed36 · 12-26-2008, 05:34 PM

To be quite honest, you would be better served if you would list all your specs including the video card, motherboard, etc...also, be sure to list what power supply you have including brand name.

**magnethead** · 12-26-2008, 06:15 PM

Quote:

Originally Posted by BoT

for most upper and high end video cards you will need 24a on that rail.
many companies offer multiple rails with lower amperage which will not suffice properly
you should look at psu's of at least 550w and up. a good quality psu with 500w - 600w could suffice but if you go for a lower end product you should look for more wattage.

you should not calculate the wattage need of your system and buy a psu based solely on that number. you should take in consideration that the performance of the psu deteriates over time as well as the integrity of your componants. by doing so your psu will not be able to continuesly supply the power it was originally rated for, heat is a factor here as well. many of your componants as they age will experience voltage leakage and starting to use more wattage.

you should also not run the psu at 100% continuesly. a good measure would 70% - 80% and 90% - 95% at peak.

how did you calculate your systems power consumption and did you consider all options?
what about future expandability?

very good info.

12-26-2008, 04:28 PM	#1 (permalink)
flare Registered User Join Date: Dec 2007 Posts: 61 OS: xp, service pack 2	Question about powersupply Ok so am looking at buying a video card that has 350watts usage My powersupply is 400watts but with the all the things it takes it is down to 348 watts Now the question is do I look at the 348 watts or the 12v rail since i have 2 12v rails-18 so 12x36 is 432. Or something like that. Do I look at the 348watts that is stated on the PSU itself or the 432watts that is calculated by the 12v rails?

12-26-2008, 04:47 PM	#2 (permalink)
BoT Registered User Join Date: Dec 2008 Location: earth Posts: 447 OS: Microsoft Windows Vista Ultimate x64 My System	Re: Question about powersupply for most upper and high end video cards you will need 24a on that rail. many companies offer multiple rails with lower amperage which will not suffice properly you should look at psu's of at least 550w and up. a good quality psu with 500w - 600w could suffice but if you go for a lower end product you should look for more wattage. you should not calculate the wattage need of your system and buy a psu based solely on that number. you should take in consideration that the performance of the psu deteriates over time as well as the integrity of your componants. by doing so your psu will not be able to continuesly supply the power it was originally rated for, heat is a factor here as well. many of your componants as they age will experience voltage leakage and starting to use more wattage. you should also not run the psu at 100% continuesly. a good measure would 70% - 80% and 90% - 95% at peak. how did you calculate your systems power consumption and did you consider all options? what about future expandability? __________________ MainStation: Q9450@3.6 \| ASUS P5Q-E \| OCZ Platinum 4x2Gb PC8500 \| eVGA GTX260 \| WD VRaptor

12-26-2008, 05:34 PM	#3 (permalink)
Tumbleweed36 Asst Manager Hardware Join Date: May 2005 Location: USA Posts: 19,656 OS: XP Professional	Re: Question about powersupply To be quite honest, you would be better served if you would list all your specs including the video card, motherboard, etc...also, be sure to list what power supply you have including brand name. __________________ ---------- I don't receive email notifications of replies to subscribed threads. (Internet provider policy) Therefore, if I don't respond to your post within 24 hours, please send me a reminder PM and include the link to your thread.