Dell8400PSU peakpower?

[nsboston103]

I have read Dell rates their psu's conservative. On A post in here, someone claimed Dell's 250 watt psu has a peak power of 320 watts. Where can I find this information, Dell has no clue. The informaton I realy need is what is the peak power of Dell's 350 watt psu ? A 2nd question is, Dell has tested an ati "850xt pe" on a Dell 8400 with 350 psu. no problems. Acording to Tom's Hardware A nVIDIA 7800gtx uses less power than an x850xt pe. So should the 7800gtx work on same system ? Even though "BFG" says you need a 400 watt psu? Is it true when a card companys recomend say 400 watts that would be at the peak like in a game, say Doom3 at the most complexe level? Help me guru's and thank you.

 

[fishmahn]

Aaaah, Peak/continuous power, PSU load, etc... fun fun fun...

Most PSUs rate themselves at peak power. Continuous is usually 70-75% of peak. Dells are rated at continuous. So, to find peak you take continuous and add about 1/3 (33%). The claim here was probably either me or Crashman, and comes from years of experience and seeing them working. Its really a rough estimate, more of a educated guesstimate than a tested rating.

Where do you find this information? Only the engineer who designed the PSU for Dell AFAIK, and I don't know where to get hold of him (I'm sure he doesn't work for Dell). I doubt anyone you can get hold of at Dell, especially through their 'front door', would be able to tell you, and if you got lucky and got to talk to their design department, they probably wouldn't tell you even if they knew.

The 7800gtx should be fine on your 8400 (Your assumptions are correct).

Well, it's true that when a company says '400w recommended' they mean peak, but that point in a game @ complex level isn't necessarily peak. What they mean is a PSU rated at 400w peak. That's also marketing - they need to protect their name -, so they have to recommend a PSU powerful enough to power their card in a 'worst case' scenario. So, 400w is probably necessary with an Intel 840EE, 6 Raptor's, 4 sticks of RAM, video capture card, etc., etc., (Fully loaded, very power-hungry system - umm, come to think of it, I'd want a 500w PSU in that case... ), but you don't need near that much power with a basic low-power A64 3000+, 1 hard drive, no capture card, etc.

In that game, while burning a DVD and encoding a video, using your webcam, doing a backup to an external drive, and... (basically using all the equipment attached to the PC at the same time, at each device's 'peak' load), that would be peak (actually, not even then - hard drives pull much more power at startup than even when reading/writing). And even then, you don't want your system to load your PSU to 'peak' when the system is at peak, because it causes the PSU to get warm, overheat, wear out sooner, etc. (i.e. break)

Mike.

Wow, didn't mean to be so long... Hope it made sense. Short version: You'll be fine; there's no documentation, just experience; and yep, that's peak (pretty much).

<font color=blue>Outside of a dog, a book is man's best friend. Inside the dog its too dark to read.
-- Groucho Marx</font color=blue>

 

[nsboston103]

Thank's Mike for the info. No it wasn't to long and yes it made sense. So I did the math.Seems like I'd be fine. Here would be the config. P4 540 3.2 Prescott. i925X chipset. 2x sticks of 1024 ddr2 533. 1 DVD+RW. 1 DVD-ROM. 1 Floppy. 2x 250Gb 7200rpm sata. 1 BFG 7800gtx oc pciex16. 1 pci soundcard. 1 pci capturecard. 1 pci fax/modem. Running on that Dell 350 watt psu rated continuous. So 350 x 0.30 = 455 peak.??? If I got this card all's I'd be doing is play'n a game, not doing the 10 different things you described at same time. LOL. Don't get me wrong I do multitask. Surf 20 websites w/Firefox, I.M., and watch TV. Love the Groucho Marks line. Thanks Mike ! Oh bye the way I currently have that toilet ati x300. GPU Clock 324MHz original, Memory Clock 196MHz original. But when I play NASCAR SIM I use ati tool, GPU 444MHz (37% overclock) Memory 220MHz (12% overclock) no artifacts. Hasn't burst into flames yet, so can't be that bad of a card. Only oc it when I run the game though.So I hope I can put that BFG 7800gtx oc in with that config I mentioned. Man I can't wait. "EYECANDY" Thank you very very much agin. Have A great day/night Mike. Signed Rob.