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Was 34amps enough?

P

provoko

Gawd
Joined
Aug 6, 2004
Messages
656
I may have made a mistake in ordering enermax 535watt psu with 34amps on +12. Is that good enough to OC an opty 165 at 1.55 volts (2.6-2.8ghz) and run sli 6800 GS? Or should I return it and get something more powerful?

Opteron 165 will OC to 1.5v-1.6v volts 2.6-2.8ghz
Abit KN8 SLI mobo
2 SLI 6800 GS
2 optical drives
2 hard drives
3-4 fans
2gb ram 2.8v

I may not even get SLI. How many amps do I need without SLI w/ high OC?

Thanks.
 
I'm not sure I understand this. You're wondering if 34A is enough to power your system, but then want to return it for a 30A PSU?

I'm sure 34A is enough to power this system . . .
 
Sorry. I re-edited my topic. But what I'm basically asking is: Will 34amps be enough for the system above?

How many watts does the 6800 GS use anyways, 80 watts?
 
rough estimate, I'd say you're in the low 20A range actual draw there, so 34 is plenty to account for temperature derating and a bit of headroom yet.

If you decide to skip the SLI part, I wouldn't bother swaping the PSU. Some hassle and a restocking fee for something that's of slightly better quality for slighlty less power, no thanks.
 
provoko said:
Sorry. I re-edited my topic. But what I'm basically asking is: Will 34amps be enough for the system above?

How many watts does the 6800 GS use anyways, 80 watts?
Click to expand...

Actual power, as measured by XBitLabs is 55W
 
I like the Enermax and have already had a very good warranty experience, just replaced my 535 that I purchased last August with a cross-ship RMA with CoolerGiant (The US Enermax subsidiary).

I for one will stick with Enermax and recommend you do the same over exchanging it for a less capable supply. You'll be holding onto this one for years, I suspect.
 
35 Amps is plenty for that system. I have a PC Power and Cooling 350 Watt with a 12V amperage rating of 10A :eek:. It has been powering a DFI LanpartyUT 250Gb, A64 2800+ (2.34 GHz), 6800GT (425/1100), 2*512 MB BH-5 (now 3*), 2*80 GB HD, RAID card, ~ 6 case fans, DVD Burner, and various sound cards for over a year with no issues.
 
Opteration said:
your insane, i don't know if i would do all that on 10amps, your nuts man
Click to expand...

I actually had 2 of them. The other system with it I sold to my uncle, it had a Epox 8KDA3J, A64 3000+, 9800 (Flashed to Pro), 200GB HD, 1 GB RAM, 16x DVD Burner (added when I sold the PC a few months ago), and a 52x CD Burner. It ran great for me for over a year and is running great for him AFAIK since I saw him a few weeks ago. They were probably very underrated in the amperage area. Like I said, they have been running great for over a year, so I will keep it in my system. If they blow up, then I replace them :D.
 
Opteration said:
your insane, i don't know if i would do all that on 10amps
Click to expand...

PC Power and Cooling power supplys are conservatively rated and shows that quality not quantity in numbers can make a difference.
 
I guess someone is going to have to call me a noob on this one but Im confused.

How are you going to draw 32 amps from a home wall outlet that is on a 20 amp breaker?

Unless I read something incorrectly your asking if you want to draw 12 more amps than a standard household breaker will provide.
 
I think power supplies convert the electricity from the socket into whatever it wants.

If anything, it has two +12 rails drawing 18amps each which total to 34. Um, not sure what happens to the 2 that are left over. Must be how the amps are ran together, probably in parallel.

I'm a PSU noob too. Haha. All I know is what I learned in physics, power = current * resistance (watts = volts * amps).

But then again, you've got PSUs that say they have 22 amps each rail.

Wait, I know: A wizard did it. ;)
 
The function of a psu is to step-down (transform to a lower voltage) the 120VAC from the wall, to 12VAC, then rectify and regulate it (turn it into DC). As it lowers the voltage, the current it can provide goes up; the max is the Iin (input current) multiplied by the ratio of Vin/Vout (120/12 = 10 in this case). If the efficiency of a power supply was 100% (and it had some big 12V wires) it could provide up to a max of 20Ain * (120Vin/12Vout) = 200A on the 12V rail.

Modern psu's are really remarkable pieces of equipment. You should google switch-mode power supplies to get more info.

(Sorry for the thread-jack-age :( )
 
ethos747474nikon8989 said:
I guess someone is going to have to call me a noob on this one but Im confused.

How are you going to draw 32 amps from a home wall outlet that is on a 20 amp breaker?

Unless I read something incorrectly your asking if you want to draw 12 more amps than a standard household breaker will provide.
Click to expand...

Not quite the same thing. The wall socket would be rated for 20AMP 120VAC, the OP will be wanting to draw 32AM 12VDC.

The stepping down of the voltage allows for higher current draw (after all the same "energy" still exists, just like Einstein theorized :D ). For example, the 650W powe supplies we use at work have a current draw of 7AMPs on the 120VAC side (less when switched to 230VAC). This is why you can see hobbist "DC" arc welders that will run off a 15AMP circuit, sure you can't weld the titanic with it but more than sufficient for case mods.

Note I didn't go into the mathematics that are involved, but there are a number of good sites for the information (I tend to go back to my old Floyds technical manuals from my college days, yep it's been over 20 years but I still own my college references as the instructors teach you more where to look for the information than to try and memorize it permanently). In fact I had developed a MIDI (musical instrument digitial interface) years before Creative Labs added one to their Sound Blaster, who knows maybe they tapped my public domain information when adding it into their boards :( I don't have enough burden of proof to persue any kind of intellectual property rights though, especially since I gave it away for free.
 
To give a short explanation of the "how do you draw 34 amps from a power supply thru a 20 amp breaker" question, you can not compare current. As stated before, a power supply converts electricity. In this case converts from 120V alternating current to different sets of direct current(ie. 12V, 3.3V, 5V, etc). Since you can't compare the currents on the DC side of the psu to the AC side, you have to compare the Power. Power = current*voltage. So 34 amps on a 12V line is 408Watts of power. For 120V thats less than 4Amps of current. So a 535Watt power supply will only draw 4.46Amps plus a little more since its not a 100% efficient conversion(ie. Power supply uses like 50-100W to convert so it uses a Max of 635W on the AC side.)
 
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