7800GTX with a 300W PSU

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meatfestival

[H]ard|Gawd
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Apr 5, 2005
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I have an old spare 7800GTX that could be put to use in my girlfriend's PC. At the moment it has some kind of Radeon X300 with a passive cooler and it really chugs in WoW, and even with games like Peggle.

The recommended minimum PSU for a 7800GTX appears to be either 350W or 400W with 22A on the +12v depending on where you look. The PSU in my girlfriend's machine does have 22A on the +12v, as well as the required 6-pin PCI-E power connector. Only thing is it's only rated 300W. It's made by Bestec if I remember right. Sounds crappy.

Have tried a few PSU calculators and it looks like the power requirements of her PC (at 90% load) would only be about 250W with the 7800GTX. Should I risk it?
 
Cool, well I hooked it up, and it powered up and booted with no meltdowns, although I forgot that I'd need a DVI->VGA adapter so haven't been able to see it working. Should be alright though, and I have a couple of spare PSUs on standby should anything happen ;)
 
I wouldn't worry about that PSU- Bestec used to OEM for some big names, including Compaq and Dell IIRC. They may not be glamourous, but they're generally very reliable.
 
Uh oh. Should I be worried by the +1.5v reading?

uhoh.jpg
 
I have no idea what +1.5V is supposed to be, but I can tell you two things: it's not coming from the PSU, and the reading is probably wrong anyway. So no, you shouldn't be worried.
 
Alright, thanks for the advice. The other readings are fine (checked in CMOS too) and it survived a few minutes of Furmark so I think we're good.
 
Just in case anyone else out there decides to try ignoring recommended PSU specs, I'm resurrecting this thread to say that the PC started crashing randomly and the PSU seems to have died now. Well, the light on it flashes and the PC won't power on anyway. Oh well, backup PSU (el cheapo 450w Vcool) is working OK :D
 
meatfestival said:
Just in case anyone else out there decides to try ignoring recommended PSU specs, I'm resurrecting this thread to say that the PC started crashing randomly and the PSU seems to have died now. Well, the light on it flashes and the PC won't power on anyway. Oh well, backup PSU (el cheapo 450w Vcool) is working OK :D
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I wouldn't be surprised if your Bestec actually puts out more continuous power than a cheapo 450 watt PSU. I have no question in my mind that if that 300w Bestec was brand new, it would work great. And about ignoring recommended PSU specs. That's sometimes OK. I don't know if anyone here remembers but last October I had my doubts of trying to get a 4670 to work on a 300 watt PSU in an old HP (the psu manufacturer was Bestec :)). Any ways, the recommended PSU wattage for a 4670 was minimum 400 watts. Well guess what? Put the 4670 in there and it worked great! Never crashed or anything. Generally, PSU requirements mean next to nothing. Take the Corsair 400CX 400 watt PSU as an example. It's only 400 watts, but it doesn't break a sweat to power a 5770 (which requires 450 watts)
 
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The Bestec probably failed due to both a combined load increase and age. Remember, how much power a power supply can put out degrades over time, because the capacitors get old. I'm guessing that Bestic is probably about 3-4 years old, probably older, so it was nearing the end of its lifetime anyways.
 
I don't care who Bestec OEMs for, after what I saw last week I don't think I can take their units seriously.

I had to buy a pair of HP Elite 204F boxes last week; I needed something ASAP for a couple of my users and I didn't have time to build something myself or have something custom built locally. They're basically the same as the Elite 210Fs that Newegg sells, but with Win7 Pro, 6GB of RAM instead of 8 and 7200.12s instead of the Caviar Greens.

One of them came with a LiteOn power supply, one came with a Bestec. I took both of them apart. I was not impressed. At all. It's not visible in this picture (and I didn't get a good pic of it) but most of the caps on the secondary on the Bestec aren't seated properly (they're a solid 1/8" off the PCB) and they're held in place by caulk. Speaking of caulk, apparently the Caulk Monster had a field day with this thing because he left the evidence of it all over the place. It's just a mess. Although it's not as bad as the LiteOn unit, which appears to have accidentally the whole goddamn caulk factory. :rolleyes: In its defense though, at least the LiteOn has an Adda fan. The fan in the Bestec is a POS sleeve bearing from Jamicon that'll probably last about 40 seconds or until someone looks at it cross-eyed, whichever comes first. Cap selection? I had it noted in a wordpad file but I've misplaced it; if memory serves, the Bestec is an all Capxcon unit, the LiteOn has Elites on the primary and both Elites and Taicon on the secondary. Gross. Oh, and the best part of these units?

They're powering Phenom II boxes, right? Right. Well the max. combined output on the +3.3 and +5v rails is something like 180w, on both power supplies. On a 300w power supply. That sounds like an ATX 1.x power supply to me, not a 2.x. And considering that a HD5450 and a 945 both going flat out (FurMark + Prime95) is enough to drag the 12v rail on the LiteOn down to about 11.7v, I'd say they probably are 1.x units. I'm not saying that Bestec or LiteOn are incapable of building decent power supplies-these were built to HP's spec, after all-but I haven't seen any evidence that they can do better. I tend to doubt that HP called for the caps on the secondary to be 1/8" off the PCB, after all.

If these two are representative of Bestec's and Liteon's average product, I'd sooner use them as boat anchors than power anything newer than a P3 with them. Frankly, meatfestival, I'd just be glad the Bestec didn't nuke anything when it died.
[/soapbox]
 
Tsumi said:
The Bestec probably failed due to both a combined load increase and age. Remember, how much power a power supply can put out degrades over time, because the capacitors get old. I'm guessing that Bestic is probably about 3-4 years old, probably older, so it was nearing the end of its lifetime anyways.
Click to expand...

You could be correct. I think heat could have had sped up its demise too, the PC has terrible airflow and the air coming out the PSU was pretty toasty.
 
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