3870 - How many Amps is needed for it?

~El~Jefe~ · Post by **~El~Jefe~** » Sat Dec 22, 2007 7:51 pm

I just realized that my reboots during gaming might be from not enough amperage to my 3870.

i dont know if this is actually possible being that I have an antec phantom 350 and it has an individual pci-e connector.

System:
Asrock dualsata2
4200+ 939 dual core 2.2ghz 512KB chip
160gb spinpoint 80 HD
pioneer dvd/cd combo
Audigy 2 zs sound card

Video card: Visiontek 3870 512Mb

I am using XP, service pack 3 (which might be the problem, or who knows at this point)

I get STALKER to load, it plays for a moment, sometimes it plays for 1-2 minutes then freeze. Card does ramp up, card is hot but I dont want to pull off the heatsink and use my watercooling block on it yet until I know it isnt thecard or ATI's in general.

dhanson865 · Post by **dhanson865** » Sat Dec 22, 2007 10:27 pm

Are you a beta tester or do you really mean XP SP2?

http://www.antec.com/specs/Phantom350_spe.html mentions a second 12v rail. It may be that you have a rail imbalance one rail is listed at 16 and the other at 18 but ( 16 + 18 ) * 12 = 408 watts not counting the 5v or 3v rails so we know that is high. Looking at the review on SPCR it looks like all the specs are high so maybe it's just a thermal limit.

If you have another PSU laying around you could always swap and see if the problem goes away.

~El~Jefe~ · Post by **~El~Jefe~** » Sun Dec 23, 2007 12:15 am

so power isnt the issue then im guessing?

i know in total this psu could handle my system, but i wonder about the needed amperage where it is, um, needed.

Service pack 3. yes im a beta tester. anyone can be

two lines you edit on your compy and it opens up service pack 3

worth it?

eh

djkest · Post by **djkest** » Sun Dec 23, 2007 8:44 am

Well, the diff for me between 2D CPU load and full 3d load is about 90W, so that would be less than 9amps. Still, the phantom may be struggling. I'm not sure if there is a scientific test to find out for sure.

~El~Jefe~ · Post by **~El~Jefe~** » Sun Dec 23, 2007 9:44 am

burebista · Post by **burebista** » Wed Dec 26, 2007 7:11 am

~El~Jefe~ wrote:I just realized that my reboots during gaming might be from not enough amperage to my 3870.

You need less than 7A from 12V.

djkest · Post by **djkest** » Wed Dec 26, 2007 9:00 am

It could be that your voltage is dropping below a critical level.. or maybe you have a defective card. Kinda hard to say.

~El~Jefe~ · Post by **~El~Jefe~** » Wed Dec 26, 2007 9:01 pm

I think it could be due to heat or a defective card.

I am unsure as to what though at the momment

deprenyl · Post by **deprenyl** » Sat Dec 29, 2007 12:04 pm

my x1950pro required 32amps on the 12v (as listed on the ati website), im pretty sure the 3870 will be around that level also. also had rebooting troubles when i first tried to load up games with my x1950pro when i had a 400w, 14amps on the 12v psu. Changed to a 36A on the 12V rail psu after

. smooth sailing.

plympton · Post by **plympton** » Sat Dec 29, 2007 4:25 pm

deprenyl wrote:my x1950pro required 32amps on the 12v (as listed on the ati website), im pretty sure the 3870 will be around that level also. also had rebooting troubles when i first tried to load up games with my x1950pro when i had a 400w, 14amps on the 12v psu. Changed to a 36A on the 12V rail psu after . smooth sailing.

Something is crazy wrong with that number.. I mean, 32a * 12v = 384 friggin' watts? No way, man, that sounds like too much.

Now, maybe there's a start up draw, or all other components + 1950 require this... I dunno. Or you just need a PSU with 36a label, which is a bit generous.

From all I read, the 3870's require about 120 watts max, which would be 10 amps, assuming it's all drawn from the 12v line.

-Dan

HueyCobra · Post by **HueyCobra** » Sat Dec 29, 2007 7:17 pm

dhanson865 wrote:Are you a beta tester or do you really mean XP SP2?

The Windows XP Service Pack 3 Release Candidate has been publicly available for a while. Nothing particularly special about it, although it purportedly increases performance. I haven't noticed any difference in typical usage.

plympton wrote:
deprenyl wrote:my x1950pro required 32amps on the 12v (as listed on the ati website), im pretty sure the 3870 will be around that level also.
Something is crazy wrong with that number.. I mean, 32a * 12v = 384 friggin' watts? No way, man, that sounds like too much.

The card manufacturers standardly "recommend" or "require" such unrealistic figures to hedge against generic/low-quality PSUs that many users have.

~El~Jefe~ · Post by **~El~Jefe~** » Sat Jan 05, 2008 9:59 pm

lol, i just read this.

nice.

yeah 400 watts is a bit of a stretch. 2 8800gt's sli'd possibly

mattthemuppet · Post by **mattthemuppet** » Sun Jan 06, 2008 9:42 pm

if it's heat (card or PSU), just turn up your exhaust fan. If it stops freezing/ gittering then that's the problem. Happened to me recently when it hit 35C inside - my 7300GT only has a 80mm S1A @5V pointed at it, so it doesn't get alot of air. Upping the DS12SL exhaust from ~550 to 900rpm solved the problem and wasn't that much noisier.

Compared with the hassle of RMAing a card or buying a new PSU it'd be worh a try at least

3870 - How many Amps is needed for it?

3870 - How many Amps is needed for it?

Re: 3870 - How many Amps is needed for it?