ATI Radeon HD 4870 power requirements overstated

[aphelion]

I just installed a VisionTek HD 4870 and wanted to give it a shot with my old 430W Thermaltake PSU. It has a single 12V rail @ 18A.

Lo and behold, after hours of stress testing all components I haven't had any problems. Here are all the power draining components:

- Gigabyte GA-P35-DS3L
- Intel E6420 (ES) @ 2.13GHz
- 4 x 1GB G.SKILL DDR2-800 @ 800 MHz
- 5 drives: 750GB Seagate, 750GB WD, 500GB WD, 400 GB Seagate, NEC DVD-RW
- WN311T RangeMax 802.11n Wireless PC PCI Adapter
- VisionTek HD 4870 512MB

The Thermaltake doesn't even have two 6-pin power adapters so I used the dual molex adapter that came with the 4870.

 

[Kari]

18A*12V=216W

4870 uses 130W tops
http://archive.atomicmpc.com.au/forums.asp?s=2&c=7&t=9354&p=0

HHDs like 10W a piece, 50W combined, most from 12V line, little from 5V as well.

CPU around 50W (questimate, too lazy to search...) afaik also from 12V line

So I'd say that PSU is under some serious strain, espcially since it's 'old'. Care to post again when it pops?

 

[aphelion]

If that happens will it go out quietly or take some components down with it?

Slightly off topic but the 600W (dual 12V rails @ 18A each) OCZ PSU I ordered has different fan placement than my existing PSU. Its fan would be facing a metal wall no matter which way it's turned. This is a death wish too, right?

 

[Homeboy2]

Yup. i expect you mean it has a top fan. cut a hole in the top of your case. problem solved

 

[Zecow]

doh... your rig is not going to consume more than 400 watts. I'm using a 4850 crossfire on a 550watt psu, OC'ed quad, 4 drives. But you're stressing ur psu.
A 4870x2 crossfire runs at 850 off the wall.. at 80% effeciency, we're talking about 650wat total consumption.
Its overstated coz each system are different. They need to overstate it for some headroom.

 

[megamanx00]

^ Yeah there's that, since some have a CPU that's rated for a crazy 125W by itself.

Another reason to overstate it is because some users might have the bright idea to go with a really cheap PSU that can't sustain 70% of it's rated output before bursting into flames . Anyway, it looks to me like you might be pushing that PSU a little. I would monitor the voltages if I was you, but if they aren't fluxuating too much, you don't hear any high pitched whine from the PSU, and everything seems stable then you should be fine. Just make sure your PSU doesn't overheat, and keep in mind that the more you push your PSU towards its Max, the shorter its lifespan.

 

[dotfader]

yeah i tried the exact same setup but its not enough juice .i had to upgrade to an antec 650 watt ps.

 

[JohnnyLucky]

dotfader - This thread is one year old. The Original Poster is long gone. Please pay attention to the dates.