sufficient supply

[Gannef]

Hi

I'm looking to do some overclocking on my 2 9800gt's (like 15% higher clocks), I currently have a 700w psu, will it deliver sufficient power to do it?

My specs are
mb - asus striker 2 nse (nforce 790i)
cpu - intel q9450 (stock 2.66ghz)
4x1gb 1333mhz ocz reaper (1.5v)
2x foxconn 9800gt 512mb
700watt psu
2x500gb hdd seagate 7200.9

 

[fffblackmage]

Yes.

 

[Gannef]

ok thanks ^^

 

[fffblackmage]

lol

You didn't mention what model or at least the brand, but I just hope you have a decent quality PSU.

The part I'd worry about is the Amp rating on the 12V rail. Just knowing the psu is rated for 700W doesn't really mean all that much, especially when some cheap psus are rated in unrealistic test conditions and some have overrated useless rails.

I'm not expecting you to run into problems, but just FYI.

 

[Gannef]

Well, I'm just a newbie with these kind of things but i'll add some more details just in case:

The psu is a ocz gxs700

The amp rating on the 12v rail is 18A.

I was just wondering, you see I ordered this system at a shop, told 'em most of the things I wanted in my pc, but I'd only mentioned that I wanted a 700-800w power supply in it, because I didn't know anything of psu's, the only thing I was sure about was that it had to be atleast 600w, they chose one, it worked..

 

[PM650]

http://www.jonnyguru.com/modules.php?name=NDReviews&file=print&reid=24
http://www.pcper.com/article.php?aid=333&type=expert&pid=1

That gamexstream isn't a terrific unit, but it's about what you'd expect from a 4-year old unit that was around $120 retail in 2006. It stood up to operating at 100% load in the hot-box without shutting down, so it's probably good for maybe ~350W for video cards, depending on what else is drawing power.

 

[Gannef]

So if i'm correct
the 2 videocards are 105w each maximum (according to nvidia's website)

that's 210w
they are both on a 12v rail with 18 amps
12x18= 216w per rail
that's 216-105=111w left that is still usable

so there shouldn't be any problems, am I right?

 

[PM650]

Should be fine as you calculated. Just remember, the max limit per rail can't be approached on all rails at the same time - 18A per rail with 4 rails = 864W, so you can only say 216W per rail (for 2 rails) when the total system load (not including vid cards) is under 248W (680 - 2*216), less if you leave room for margin (say 200W rather than 248W).

My estimate still remains, 350W for cards = 175 max per card to allow some margin. I'm betting you won't hit 150W without water cooling or some other exotic cooling.

 

[Gannef]

I think you're right on that point, if the heat would increase linear with the speed (which won't happen ofcourse) the maximum I could get out of it would probably be around 15% more although I find that pretty optimistic.. but i'll give it a try

thanks for the info