To 6800 GT/Ultra owners (reg SMPS)

[TheGuru]

I am really pi**ed off with all the SMPSs I have been able to lay my hands on. I have tried out Mercury 350 Watts and Zebronics 500 Watts, but I am not too happy about their performance.
The issue is with the voltage on the +12V line - it just doesn't stabilise. It keeps varying from 12.09 to 11.74 which is sickening.
I like to see how things are with others (especially with antec). Can you post a graph or some such by stressing your video card a bit (play games... and see how the voltage varies on +12V line)? I use Asus PCProbe to monitor the voltages.
You may use one of these to monitor voltages if you are not using Asus MB:
http://www.almico.com/speedfan.php
http://mbm.livewiredev.com/
I have absolutely no idea about these software and by no means do I recommend them
Oh! And do mention the SMPS you are using. Thanks!

Well, i got a Antec TruePower 430W SMPS, although I got a FX5900XT, it is enough for me, even more, this one is enough for a 6800 series

[TheGuru]

it is enough for me, even more, this one is enough for a 6800 series

How do you measure that? By monitoring how stable a voltage it can deliver on the +12V rail. That is precisely what I want to know. Infact, I am looking at either Antec True430 or Antec True480 - maybe even Powersafe, but stability on +12V is what matters.

[funkymonkey]

you have some wrong info.
On all PSUs the voltage will vary a bit.
you should worry if its dropping below 11.4V
11.74 is perfectly fine.
I have 6800GT and VIP GOLD 450W PSU.
My 12V voltage rail is at 11.99V most of the times and varies from 11.91-11.99 so its perfect is you call it.
But my friend has Zebronics 500W PSU and he also have 6800GT.
His voltage rail varies from 11.6-11.99V and there is absolutely no stability or performance issues on his system either.
Its not the voltage that matters themost the Ampere rating of the PSU.
Make sure your PSU has atleast 18A on 12V line and 40A on 5V line.
This is what matters for stability.

[TheGuru]

My 12V voltage rail is at 11.99V most of the times and varies from 11.91-11.99 so its perfect is you call it.

Yes, I'd say that is a "good-enough" perfect voltage if that is the case even when you are playing graphics-intensive games (like doom 3 or HL2).

His voltage rail varies from 11.6-11.99V and there is absolutely no stability or performance issues on his system either.

The way I see it, this voltage variation is an absolute no-no. It is my belief that such huge variation (11.6-12.1) will simply stress-out the components too much and I don't think we really get long-term (read this as 3-6 months) stability and reliability.

Its not the voltage that matters themost the Ampere rating of the PSU.
Make sure your PSU has atleast 18A on 12V line and 40A on 5V line.
This is what matters for stability.

Amperege rating is a different matter. 18A is supposedly good-enough for a GT though I personally prefer atleast 20-22A.

The actual question is how much "sustained" (under max load) amps can the SMPS provide on +12V rail? 18 to 20 is good enough. However, if it is not providing this under a stable voltage, what good is it? It is as if saying that you provide anywhere from 16 to 19A on +12V??!!?? (though maybe not such huge variation) A stable voltage definitely counts towards the system stability and reliability. And THAT is what I am looking for.

I have no idea why you would need 40A or 50A (in case of Zebronics 500) on +5V. Most of the components we provide power to are to HDDs, optical drives and video cards which all need to operate off the +12V rail. This merely goes to show the poor quality of these power supplies. 50A on +5V and just 18A on +12V??!!??

[funkymonkey]

+5V Amp rating is critical if you have lots of optical drives and HDDs.
I have 4 HDDs and 3 optical drives in my PC.
I went for gold series as it has 24A on 12V line and 48A on 5V line.
It was very hard to find and i got it for premium price of 3.5K about a year ago.
The brand name of my PSU is Starnet. I removed the sticker on the PSU and below that was Thermaltake logo.
So I am guessing its TT truepower OEM which is rebramded as VIP or starnet in India.
I dont know where do you stay but here in mumbai there are dealers who sell imported TT truepower and Antec PSUs at andheri.
Its pure luck, sometimes they have it in stock and sometimes they dont.
I even found 1 shop selling TT Xaser III cabinet with TT Truepower 500watt PSU.

[TheGuru]

http://www.antec.com/pdf/article/info_DIYArticle1.html
http://www.antec.com/pdf/article/mob...age_test.html#

Makes me wonder.....

[funkymonkey]

I have the multimeter.
I will check it out myself.

[TheGuru]

Cool! If possible, please check out the Zebronics 500 that your friend has as well. Thanks!

[funkymonkey]

haha..
I just checked it.
My VIP gold was stavle 12.00V exactly as it should be.
Zebronics 500 11.94 stable.
And for fun i checked generic 300watt which i use for my old p3 machine.
It was 11.81V but that too stable.

[TheGuru]

Cool!!! Thats good news. Was it that stable even through "heavy" games? Makes me wonder...

[funkymonkey]

I had rthdribl running. the most stressful 3d demo out there.
But it really didnt made any difference when at idle or in demo. Just minute 0.01V dip and it went back to original.

[TheGuru]

Thanks man!!! I really appreciate your inputs.
Now wheres that multimeter my uncle had? Lets do some more R&D!

I think it all checks out. I recently got the APC 1KVA UPS and I observed that the power it was providing was at around 220W on no load and went upto 300W when playing D3. And this load in including the 17" monitor. I have 2 S-ATA drives, 1 IDE and 1 DVD drive. And of course the 6800 GT. So, I reckon that the load can never go beyond 300-350W which is the SMPS rating that should be good enough.
Now, the only other thing that matters is the amperege on +12V and any SMPS that can deliver 18A and plus consistently should do and I think this is what is really going to differentiate different SMPSs.

But then, how exactly would you differentiate between a Zebronics and an antec SMPS???!!?? How can antec justify its higher price (apart from the brand name)? There has to be a catch somewhere...........

[[poWer]]

Well I hav Got a OCZ-550 SMPS enough 2 [poWer] my Gainward 6800 Ultra PCI-E GFX card and Athlon 64 3800+. One thing 2 b noted down nVidia itself said that Atleast a SMPS of 480Watt is necessary 4 6800 NonUltra/GT/Ultra gfx cards.

[funkymonkey]

Well thats not true. Nvidia revised their statement long time ago and said 350 watt quality PSU will be enough.
And you know this 6800GT runs fine in my 2 year old shuttle PC that i bought from Singapore which has only 250watt PSU.
It all depends on quality of PSU and components installed on your computer.
I cannot test the amperes using my multimeter. It dosent show any reading.

[TheGuru]

nVidia did revise their statement regarding the power supply required. It actually checks out based on actual data that I mentioned previously. I have a P4 3E, Asus P4P800 E-Deluxe, 1GB DDR400 RAM (dual-channel), 2 S-ATA drives on RAID1 and one IDE drive plus a DVD-ROM. Oh! and a creative Audigy 2 ZS and the eVGA 6800GT. This, along with a 17" SyncMaster drains a maximum of 300W from the UPS. So, for the system alone (without the monitor and even with an Ultra), 350W really ought to be good enough, though I personally prefer 430W.

I don't think you will be able to test the amperege since the equipment need to put some load and derive some current as needed, else no current really comes out. You can see that they are using some special equipment to test the same (the link I posted before).

(And, lo and behold, that will be my 50th post :-)

[[poWer]]

Originally Posted by funkymonkey

Well thats not true. Nvidia revised their statement long time ago and said 350 watt quality PSU will be enough.
And you know this 6800GT runs fine in my 2 year old shuttle PC that i bought from Singapore which has only 250watt PSU.
It all depends on quality of PSU and components installed on your computer.
I cannot test the amperes using my multimeter. It dosent show any reading.

well nVidia may hav revised it but one thing U said is 100% tru that PSU's quality really matters.Anyway thanx 4 the updated info on PSU.