CNET Discovers Power Problems w/512MB 7800 GTX SLI Cards and FX-60 CPUs

[zephyrprime]

Originally posted by: Matthias99
As hinted at in the article, it's probably a power balancing issue -- the way the systems were configured was putting too much load on one rail of the PSU.

I always thought that this "multirail" thing was never a good idea because of this exact issue.

 

[Woofmeister]

Ronin's response leads me to believe that CNET's and Matthias's conclusion is correct--it probably is a load balancing problem with these particular systems. But the reason why I posted the article is because I think it's a harbinger of what to expect in the coming months. Larger PSUs will become a necessity very soon whether you go with G71s in SLI or R580s in Crossfire. That means more heat and more noise even if you're water cooling. It also means that those of us who thought we were future proofing by springing for 600watt PSUs were (as usual) underestimating the relentless march of high-end personal computer technology. Call this a cautionary tale.

 

[Nirach]

I think it's time to start building an external housing for a PSU.. Seeing as I, believe it or not, have no space inside the case to fit a second one.

You never know what the future holds, and all that nosh

 

[zephyrprime]

I'm looking at the power supply figures a little more and here is my speculative take on it:
I'm assuming that on the enermax power supply, since it has 2 12V rails, 1 rail is for the gpus and the other one handles everything else. If this is the case, then the 1 rail with only 216 watts tops would not be quite adequate if nvidia specs of 120 peak are to be believed. I believe xbit meased a little more than 100 watts for a 7800gtx512.

On the other hand, the Silverstone has 4 rails. I'm guessing 1 for cpu, 2 for gpu, and 1 for HD and everything else? The rails vary in their capacity but that power supply should have more than enough power for 2 7800gtx512's unless someone connected the rail intended for use with peripherals to one of the graphics cards?

I still don't quite buy cnet's claims though. Don't quite a few people here on AT have the same sort of setup? I haven't heard any problems from anyone before with a 600W power supply.

Wait, I forgot something. Even though graphics cards draw mostly off the 12V rail, they don't draw entirely from that rail. There's still some power draw off of the 5V rail and that should give the Enermax adequate capacity.

 

[Acanthus]

Its the damn dual rail 12v lines that cause the stability problems.

Too much load on one of the 2 lines can wreck havoc on a system.

 

[Nextman916]

Lets face it sooner or later were all gonna have an external powerbrick dangling from our systems, like 360's!

 

[nRollo]

Originally posted by: Nirach
I think it's time to start building an external housing for a PSU.. Seeing as I, believe it or not, have no space inside the case to fit a second one.

You never know what the future holds, and all that nosh

There used to be a company that made cases with a couple spots for PSUs. BFG was joking, but I think it's a good idea to have dual PSUs. 2X450W is cheaper than 1 900W, having one psu just to power two high end cards like 512 GTXs or X1900XTXs seems reasonable to me.

 

[5150Joker]

I'm actually modding my system to use dual PSU's. I'm working on creating an adapter so I can link two PSU's together and relieve the load on my Antec so yeah, dual PSU's for the future might become a necessity if you want to play with high end cards in dual card configuration or like to OC a lot.

 

[Ackmed]

Or just buy a really good quality PSU, such as the a PC P&C as I did.

 

[5150Joker]

Originally posted by: Ackmed
Or just buy a really good quality PSU, such as the a PC P&C as I did.

Yeah or you could do that but I think just the ability to mod my system and add in a second PSU would be fun in itself heh.

 

[Gstanfor]

Originally posted by: Rollo

Originally posted by: Nirach
I think it's time to start building an external housing for a PSU.. Seeing as I, believe it or not, have no space inside the case to fit a second one.

You never know what the future holds, and all that nosh

There used to be a company that made cases with a couple spots for PSUs. BFG was joking, but I think it's a good idea to have dual PSUs. 2X450W is cheaper than 1 900W, having one psu just to power two high end cards like 512 GTXs or X1900XTXs seems reasonable to me.

You'll be wanting a coolermaster stacker case. Even includes the necessary cable to link 2 PSU's together.

 

[Pete]

<ignorance>I thought these PSUs with "multiple rails" really just have multiple lines, thanks to ATX spec limiting one line to around 18A @ 12V due to wire gauge. I thought all these lines just ran back to a single rail. When you say rail imbalance, do you all mean not enough +5V or even +3.3V for the apparently huge +12V load of newer GPUs and CPUs/MBs? Ronin's extra HDs might tax his +5V rail more and so balance his +12V draw.

As I understand it, the key may be to make MBs lean on the +5V lines some more, or just shift the PC and so PSU focus to +12V. Or just buy Antec TruePowers with their totally separate rails, tho I've read of some Antec issues of late.</ignorance>

 

[Sentry2]

Originally posted by: Pete
<ignorance>I thought these PSUs with "multiple rails" really just have multiple lines, thanks to ATX spec limiting one line to around 18A @ 12V due to wire gauge. I thought all these lines just ran back to a single rail. When you say rail imbalance, do you all mean not enough +5V or even +3.3V for the apparently huge +12V load of newer GPUs and CPUs/MBs? Ronin's extra HDs might tax his +5V rail more and so balance his +12V draw.

As I understand it, the key may be to make MBs lean on the +5V lines some more, or just shift the PC and so PSU focus to +12V. Or just buy Antec TruePowers with their totally separate rails, tho I've read of some Antec issues of late.</ignorance>

I had problems getting my GTX 512's I had to boot on my DFI expert with a Silverstone 650W ps. DFI tech support told me it was probably a load balancing problem between the 5v and 12v lines in the ps. They recommended getting a supply with 1 12v rail. I hope I don't have the same problem with the G71's on this board. The GTX 512's ran fine in SLI on an Asus A8N Deluxe so I don't know what the deal is.

I thought about getting a pc power & cooling 1KW but I'd hate to spend almost $500 just to have the same problem because of multiple 12v rails.

 

[Polish3d]

How about just making these cards so they just plug into the damn wall

 

[dev0lution]

Irony is the teeter totter of AMD and Intel trying to reduce power consumption as ATI and NVidia do all they can to increase it :laugh:

 

[Acanthus]

I think external power bricks are the only way after a couple more generations, graphics cards are already the highest power draw part of a system, multicard solutions are only going to get more and more rediculous as time passes.

They met and ran over the power requirements of PCI-Express by the time it became mainstream, unless we want to revisit the "finding 4 molexs on their own rails for graphics cards".

Its pretty much the only way to go.

 

[nib95]

So does that mean I should spent the extra £35 and go for the Enermax Liberty 620w over the 500w?
Bearing in mind I will be running and OC'd Opteron 170 and X1900 XTX and most likely in future Crossfire

 

[Painman]

That Liberty has an awfully nice combined 12V rating, but it's still dual rail, that irks me

If you're OK with spending > $200 on a PSU, maybe PCP&C is the way.

Or maybe ATi is looking at worst case scenarios. Who knows. I don't have a heavily laden machine, my 36 amps could probably do it, but it would suck if it couldn't. I bouught it to keep around for a while.

PSU makers need to kick with some PSUs that are heavier on the +12v line. Or someone needs to come out with some 12v only PSUs that are > 180W and don't cost a fortune. Right now those are all rather expensive industrial PSUs - heavy duty, but mostly over $150.

 

[nib95]

Originally posted by: Painman
That Liberty has an awfully nice combined 12V rating, but it's still dual rail, that irks me

If you're OK with spending > $200 on a PSU, maybe PCP&C is the way.

Or maybe ATi is looking at worst case scenarios. Who knows. I don't have a heavily laden machine, my 36 amps could probably do it, but it would suck if it couldn't. I bouught it to keep around for a while.

PSU makers need to kick with some PSUs that are heavier on the +12v line. Or someone needs to come out with some 12v only PSUs that are > 180W and don't cost a fortune. Right now those are all rather expensive industrial PSUs - heavy duty, but mostly over $150.

I dont know anything about rails etc.

Enermax being Dual rails? Good or bad thing? :s

Basically, here are my choices.
For under a £100 what would you guys get?!

Ultimate respect forever for anyone who helps me!
P.S It has to be black to match my case!

http://www.overclockers.co.uk/acatalog/Online_Catalogue_Power_Supplies_123.html

 

[Nirach]

Originally posted by: Rollo

Originally posted by: Nirach
I think it's time to start building an external housing for a PSU.. Seeing as I, believe it or not, have no space inside the case to fit a second one.

You never know what the future holds, and all that nosh

There used to be a company that made cases with a couple spots for PSUs. BFG was joking, but I think it's a good idea to have dual PSUs. 2X450W is cheaper than 1 900W, having one psu just to power two high end cards like 512 GTXs or X1900XTXs seems reasonable to me.

Aye, but I'm not really in the market for a new case at the moment, not wiith the level of modification on mine to get it the way I want. I do, however, have a thermaltake Aquarius three housing lying around, and with some drilling, tapping and standofs, that could take a PSU.

 

[otispunkmeyer]

Originally posted by: nib95

Originally posted by: Painman
That Liberty has an awfully nice combined 12V rating, but it's still dual rail, that irks me

If you're OK with spending > $200 on a PSU, maybe PCP&C is the way.

Or maybe ATi is looking at worst case scenarios. Who knows. I don't have a heavily laden machine, my 36 amps could probably do it, but it would suck if it couldn't. I bouught it to keep around for a while.

PSU makers need to kick with some PSUs that are heavier on the +12v line. Or someone needs to come out with some 12v only PSUs that are > 180W and don't cost a fortune. Right now those are all rather expensive industrial PSUs - heavy duty, but mostly over $150.

I dont know anything about rails etc.

Enermax being Dual rails? Good or bad thing? :s

Basically, here are my choices.
For under a £100 what would you guys get?!

Ultimate respect forever for anyone who helps me!
P.S It has to be black to match my case!

http://www.overclockers.co.uk/acatalog/Online_Catalogue_Power_Supplies_123.html

1st choice might be shopping at scan.co.uk......overclockers tend to be the most expensive place ever for parts in the UK

scan, micro direct, ebuyer are usually cheaper

 

[MrSpadge]

I'd take a different approach to this problem: lower the clock speed of the graphics cards a bit and lower the voltage considerably. This might cost you 15 - 20% speed but get the (X1900) cards back to 50 - 60W. Then you could easily handle 2 of them in a system. This won't give you the top 3DMarks, but so what
And it would be nice to see low-k dielectrics back in TSMCs process, be it 90 or 80nm.

MrS - running a 6600GT on a 19" CRT just fine

 

[nib95]

Originally posted by: otispunkmeyer

Originally posted by: nib95

Originally posted by: Painman
That Liberty has an awfully nice combined 12V rating, but it's still dual rail, that irks me

If you're OK with spending > $200 on a PSU, maybe PCP&C is the way.

Or maybe ATi is looking at worst case scenarios. Who knows. I don't have a heavily laden machine, my 36 amps could probably do it, but it would suck if it couldn't. I bouught it to keep around for a while.

PSU makers need to kick with some PSUs that are heavier on the +12v line. Or someone needs to come out with some 12v only PSUs that are > 180W and don't cost a fortune. Right now those are all rather expensive industrial PSUs - heavy duty, but mostly over $150.

I dont know anything about rails etc.

Enermax being Dual rails? Good or bad thing? :s

Basically, here are my choices.
For under a £100 what would you guys get?!

Ultimate respect forever for anyone who helps me!
P.S It has to be black to match my case!

http://www.overclockers.co.uk/acatalog/Online_Catalogue_Power_Supplies_123.html

1st choice might be shopping at scan.co.uk......overclockers tend to be the most expensive place ever for parts in the UK

scan, micro direct, ebuyer are usually cheaper

For some things they are, but for other (at the moment GPU) they are cheaper. Plus they do speciality items unavailable at other sites. So if your gonna order, order from them in in one go and you save on shipping.

So which PSU?

I'm still steering towards the Enermax Liberty 500W.
Just not sure this will be sufficient.

For around the same price I can get the Thermaltake Purepower 680w, or the Hiper Type R 580W.

Which do you guys think would be best?

Or I could spent £35 more and get the Enermax Liberty 620w.

 

[Vinnybcfc]

Get the Enermax Liberty 620w but I would have to agree to look elsewhere to buy your stuff, how much cheaper are there graphics cards atm?

 

[Jon1234]

Originally posted by: nib95

I dont know anything about rails etc.

Enermax being Dual rails? Good or bad thing? :s

Basically, here are my choices.
For under a £100 what would you guys get?!

Ultimate respect forever for anyone who helps me!
P.S It has to be black to match my case!

http://www.overclockers.co.uk/acatalog/Online_Catalogue_Power_Supplies_123.html

Hiper seem to offer good value in the UK, it may be that your requirements extend beyond even their most powerful model though...