Need to replace PSU: Zalman 850w and 1000w

t1000 · Post by **t1000** » Sat Dec 13, 2008 3:07 am

Hi there all.

I'm a silence fan and need to replace my PSU (Seasonic 650w) as it will no longer stay stable following the installation of a Nvidia GTX280 (also have 4 hard drives, 2 optical, soundcard etc).

I was looking at either the 850w or 1000w HP Zalman PSU. I've read good things about the low noise levels of the 1000w model.. does the 850w share these qualities because 1000 seems to be overkill for me and I can save a few bucks opting for the 850w model.

Cheers

1000

lucas82 · Post by **lucas82** » Sat Dec 13, 2008 4:22 am

Why not 1500W? joking, 650W should be enough.

What processor you got? Is it overclocked?

t1000 · Post by **t1000** » Sat Dec 13, 2008 1:13 pm

nothing overclocked. THe simple fact is that the PSU won't drive my rig since the card was installed.. it was 100% rock stable beforehand so it's definitely a PSU issue (the card itself is not faulty).

Back when I had a 4870 in there the PSU would also ramp up it's fans to jet-engine speed within a few mins, indicating that the PSU was under very heavy load.

1000

jaganath · Post by **jaganath** » Sat Dec 13, 2008 2:56 pm

THe simple fact is that the PSU won't drive my rig since the card was installed.. it was 100% rock stable beforehand so it's definitely a PSU issue (the card itself is not faulty).

if the pc is not stable following installation of the GTX280, it doesn't necessarily follow that the PSU is to blame. it could be buggy VGA card drivers, or the extra heat from the GTX280 is causing system temps to exceed safe limits.

Back when I had a 4870 in there the PSU would also ramp up it's fans to jet-engine speed within a few mins, indicating that the PSU was under very heavy load.

PSU fan speed is not based on load but on internal temperature. it could be that you simply have inadequate case cooling and the PSU is having to do more than it should.

t1000 · Post by **t1000** » Sat Dec 13, 2008 4:16 pm

Guys - my temps are fine. Temps are now lower than when the 4870 was installed because the GTX280 is venting heat through to the back of the case whereas the 4870 with the AC Twin Turbo was leaving the heat inside the case. I've measured it.. the temps are fine.

My PSU is and has been rock solid. There is nothing wrong with any other part of my system. I have 6 nexus fans installed in a well ventilated P182 case.

Is there any possibility that somebody could find the time to comment on the actual question I had initially ? It's not that I don't appreciate the advice, it's just that I need the original question addressed to help me make an actual decision.

1000

Post by **MikeC** » Sat Dec 13, 2008 4:43 pm

Zalman 850 has the same basic acoustics as the 1000, tho you'd expect it'll ramp up at a wee bit lower temp/load. Should do you fine.

t1000 · Post by **t1000** » Sun Dec 14, 2008 4:56 pm

Thanks Mike, much appreciated. I might just extend to the 1000w anyway.. at some point in a year or two I might have a brain-snap and try SLI.

Cheers

1000