Seasonic M12 700 NOT enough for 8800GTX SLI????

[Lazaredz]

Per nvidia site:

http://www.slizone.com/object/slizone_b ... ersupplies

It rates for the 8800GTS though.

So, true statement or nvidia covering their butt by making sure everyone has MASSIVE overkill and thus they don't have to hear the complaints about "XXX PSU didn't work and its rated at 1.21 Gigawatts!!!"

What do the PSU gurus think???

[Howard]

It's perfectly fine, unless one happened to have two top-end quad-core CPUs, 8 hard drives, a shitload of fans and pumps, etc.

[EsaT]

It's well enough for two 8800GTX, according to nVidia TDP of single cards is ~180W.


And in fact there's some higher rated PSUs I would demote from that list, for example for example that Silverstone 750W, only ~50W more from 12V and you've got problem of multiple rails.
Also that Coolermaster 850W, if it's anything like previous Coolermasters it's going to have lot of low current limited rails with very low combined 12V output compared to total power rating.

[Lazaredz]

That is what I thought.

Thx

[Shadowknight]

What's funny is that I see stuff like this asked a lot on a couple of other forums. It's always X PSU is rated for 500w/600w/700w/750w/800w - will it be able to handle the next generation of cards? Sheesh, at that rate you might as well just get one of the 1000/1100w PSUs and call it a day, though I'm sure there will still be people who ask if THOSE will be enough to run a new system. Maybe they should just get a case that hold two PSUs and get two 1100w ones, plus the Thermaltake VGA PSU that's been advertised, though I'm sure Nvidia/ATI will still say those won't satisfy the minimum recommended specs.

[student]

I would go with what nVidia recommends. Spec sheets don't always translate to reality, and I assume nVidia has actually tested those combinations.

Perhaps two 8800GTX's in sli create particular power demands that may de-stabilise the power output of the M12-700 in real life? Who knows.

I recently got a X1900XT and the 24A 12V rail on my 380W Antec True PSU couldn't cope in extreme situations, although the specs and reviews I read said it would work fine...

[EsaT]

Perhaps two 8800GTX's in sli create particular power demands that may de-stabilise the power output of the M12-700 in real life? Who knows.

More than 56A load (~670W) on 12V, total load being 710W with 55C case temperature?

http://jonnyguru.com/review_details.php ... page_num=2



And then they have allowed even BFG PSU to one list despite of those being oldish designs with underpowered 12V and lousy voltage regulation under real loads.
http://www.jonnyguru.com/review_details.php?id=21

[merlin]

I would go with what nVidia recommends. Spec sheets don't always translate to reality, and I assume nVidia has actually tested those combinations.

Perhaps two 8800GTX's in sli create particular power demands that may de-stabilise the power output of the M12-700 in real life? Who knows.

I recently got a X1900XT and the 24A 12V rail on my 380W Antec True PSU couldn't cope in extreme situations, although the specs and reviews I read said it would work fine...

You had a rather old generation psu so that's not a big surprise. It doesn't even have 24 pins, so it's pretty iffy on anything using a lot of 12v power. I have to say though, I'm using the same psu on my 7900GTO with no problems...of course my overall system power is only like 150 watts or so. However newer PSU's like the S12 or M12 would do far better. I don't think going with Nvidia's recommendations make sense at all for anyone who knows power supplies. Everyone here knows that those recommendations are extremely conservative and only made for worst case situations. It's easy to calculate out a relative amount of power used and then decide on a psu based on that. Dual 8800GTX's on a M12-700 would be a piece of cake hands down.

[wwenze]

Per nvidia site:

http://www.slizone.com/object/slizone_build_psu.html#certified_powersupplies

It rates for the 8800GTS though.

So, true statement or nvidia covering their butt by making sure everyone has MASSIVE overkill and thus they don't have to hear the complaints about "XXX PSU didn't work and its rated at 1.21 Gigawatts!!!"

What do the PSU gurus think???

There goes the reliability of the list.

[sjschwinn]

I would go with what nVidia recommends. Spec sheets don't always translate to reality, and I assume nVidia has actually tested those combinations.

That's a lot to assume. It's more likely nVidia has some minimum specs they expect a PSU to have (read: listed specs).

[sjschwinn]

I would go with what nVidia recommends. Spec sheets don't always translate to reality, and I assume nVidia has actually tested those combinations.

That's a lot to assume. It's more likely nVidia has some minimum specs they expect a PSU to have (read: listed specs).

Another possibility is a manufacturer might have to PAY to have nVidia CERTIFY it as SLI ready.

[Tephras]

That's a lot to assume. It's more likely nVidia has some minimum specs they expect a PSU to have (read: listed specs).

The power supplies are tested on systems that nVidia has categorized in different "SLI PC Configurations", the configs are listed here. However, in the list of certified PSUs, there is no indication that the footnote that refers to those test configurations apply to PSUs certified for 8800GTX/8800GTS/7950GX2 cards.

[nici]

Another possibility is a manufacturer might have to PAY to have nVidia CERTIFY it as SLI ready.

That's the first thing i thought about..

[student]

Perhaps the M12-700, although technically able to cope with two 8800GTX's in Sli wasn't certified by nVidia as it was really noisy when running them? Thats the impression that the jonnyguru review gives:

"Once again, the PSU was very loud by test 4 (drawing around 400w with 43 degree intake air). Certainly the fans were spinning at full RPM; which is a good thing considering how high the temperatures were getting."

Maybe the nVidia certified PSU's have more favourable noise and tempurature profiles under typical high spec system loads? Prehaps they decided on an arbitary 750W minimum output?

Whatever the case, it just seems more prudent to follow the advice of a manufacturer who has actually tested the PSU's in real life, over the opinions of well informed enthusiasts who have read lots of reviews and done a few calculations.

Someone should build one...

The payment argument doesn't really have any relevance to this discussion, even if it were true. Why would Seasonic pay to get the M12-700 8800GTS Sli certified but then decide not to fork out for 8800GTX Sli certification?

[sjschwinn]

From http://www.slizone.com/object/slizone_howtobuild_2.html:

Note: These power supply recommendations are based on the following test configurations using standard component clock speeds:

Extreme SLI PC Configuration:
Dual GeForce 8800 GTX or Dual GeForce 8800 GTS or Dual GeForce 7950GX2
AMD Athlon 64 FX-62 2.8GHz (AM2) or Intel Core 2 Extreme X6800 2.9GHz
NVIDIA nForce 680 SLI or NVIDIA nForce 590 SLI motherboard with 2GB system memory
Two HDDs in Raid 0 configuration
Two optical drives
PCI Sound Card

[merlin]

Perhaps the M12-700, although technically able to cope with two 8800GTX's in Sli wasn't certified by nVidia as it was really noisy when running them? Thats the impression that the jonnyguru review gives:

That is definitely wrong. Many psu's are far louder than the M12-700 at something far under the same load. Of course a PSU will be very loud at near maximum output, it has to get rid of a ton of heat, this is the case with anything "certified" or not.

"Once again, the PSU was very loud by test 4 (drawing around 400w with 43 degree intake air). Certainly the fans were spinning at full RPM; which is a good thing considering how high the temperatures were getting."

Maybe the nVidia certified PSU's have more favourable noise and tempurature profiles under typical high spec system loads? Prehaps they decided on an arbitary 750W minimum output?

Uh, if you notice the M12-700 IS certified for SLI 8800GTS... The difference between that and the SLI 8800GTX is only about 80 watts or so. This is just completely arbitrary and conversative certification. it's a guideline not a rule!

Whatever the case, it just seems more prudent to follow the advice of a manufacturer who has actually tested the PSU's in real life, over the opinions of well informed enthusiasts who have read lots of reviews and done a few calculations.

You can be prudent like that, meanwhile the rest of us will get correctly sized psu's and save money/be more efficient. You'd figure seeing MikeC's article on the power usage in computers and his actual test data on system power is enough proof of what is really used and what we should size for if we think a bit.

Someone should build one...

The payment argument doesn't really have any relevance to this discussion, even if it were true. Why would Seasonic pay to get the M12-700 8800GTS Sli certified but then decide not to fork out for 8800GTX Sli certification?

The only real answer is if nvidia explains their full testing methodologies first.

Either way the #1 Key: Certification is for people who want guarantees and don't know anything about computer power. People who know their power like silentpc readers will know better how to size and measure the right psu to buy.

[nici]

"Once again, the PSU was very loud by test 4 (drawing around 400w with 43 degree intake air). Certainly the fans were spinning at full RPM; which is a good thing considering how high the temperatures were getting."

43°c intake air? Did they run it in an oven or something? Or possibly in a case with very crappy airflow and the rest of the components were also cooking. All is well if it does not go KABOOM?

Anyway, if one just wants to build a system without thinking those lists might be good. Just get everything from PSU to floppy cables to screws SLi certified. yay.

[student]

This is interesting:
http://www.jonnyguru.com/forums/showthread.php?t=271

According to dear jonny, a psu has to supply a minimum of 60A to the 12V rails in order to certify for 8800GTX in Sli. The M12-700 is excluded because it "only" has 56A on the 12V rails.

He also mentions in the thread that nVidia's SLi certification tests are pretty through, and that an M12-700 will easily manage two 8800GTX in Sli.

I think I am just obsessed with the thought of a consumer system actually NEEDING a 1KW psu. I will not be happy until that day arrives!

[student]

The 43degrees was part of a stress test. My case temps often get into that range after some heavy gaming. They never used to rise above 33 degrees with my old FX1400... sigh. I might have to turn my fans up a bit...

[jaganath]

I think I am just obsessed with the thought of a consumer system actually NEEDING a 1KW psu. I will not be happy until that day arrives!

Have you seen the cartoon posted in the VGA forum about the guy who needs a desktop power station to run his gaming PC? It's not too far from the truth.

[Lazaredz]

People who know their power like silentpc readers will know better how to size and measure the right psu to buy.

QFT!!!

And hence why I came here.

[sjschwinn]

This is interesting:
http://www.jonnyguru.com/forums/showthread.php?t=271

According to dear jonny, a psu has to supply a minimum of 60A to the 12V rails in order to certify for 8800GTX in Sli. The M12-700 is excluded because it "only" has 56A on the 12V rails.

720W from just the 12V rail(s)? That seems almost silly.

Isn't 2 8800GTXs around 375W for both, being very conservative? Add in a conservative 175W for the CPU, and another conservative 50-75 for everything else on the 12V line, you get 600-625W max, and that's being conservative!

56A is Seasonics conservative continuous rating at 40 (or 50C). That is 670W, which seems to me to be plenty.

Personally, I'd have no problem building a system with an M12-700 with dual 8800 GTXs...

[merlin]

This is interesting:
http://www.jonnyguru.com/forums/showthread.php?t=271

According to dear jonny, a psu has to supply a minimum of 60A to the 12V rails in order to certify for 8800GTX in Sli. The M12-700 is excluded because it "only" has 56A on the 12V rails.

720W from just the 12V rail(s)? That seems almost silly.

Isn't 2 8800GTXs around 375W for both, being very conservative? Add in a conservative 175W for the CPU, and another conservative 50-75 for everything else on the 12V line, you get 600-625W max, and that's being conservative!

56A is Seasonics conservative continuous rating at 40 (or 50C). That is 670W, which seems to me to be plenty.

Personally, I'd have no problem building a system with an M12-700 with dual 8800 GTXs...

Yep, you got it almost right! I'm not sure where you're getting a 175W cpu, even the quad core duo is only a thermal design of 130W. Either way that would be 375W + 130W + 100W for mobo/peripherals = 605W with completely power guzzling components. And this is only at completely maximum load on both gpu and cpu. I'd say it would be pretty hard to stretch the M12-700 to the limit without doing some serious overvolting and other shenanigans like 8 Hard drives or something.

[EsaT]

Isn't 2 8800GTXs around 375W for both, being very conservative?

TDP of card is apparently slightly under 180W.

Anandtech got 520 W (from wall) as max power draw of SLI PC, after substracting losses in PSU that would be 450W at most.

According to dear jonny, a psu has to supply a minimum of 60A to the 12V rails in order to certify for 8800GTX in Sli.

And propably no limit to how many low current limited rails that's divided.

"Once again, the PSU was very loud by test 4 (drawing around 400w with 43 degree intake air). Certainly the fans were spinning at full RPM; which is a good thing considering how high the temperatures were getting."

43°c intake air? Did they run it in an oven or something? Or possibly in a case with very crappy airflow and the rest of the components were also cooking.

In "hotbox". All heat outputted by load tester is piped to sealed case where PSU is only exhaust.

[wwenze]

This is interesting:
http://www.jonnyguru.com/forums/showthread.php?t=271

According to dear jonny, a psu has to supply a minimum of 60A to the 12V rails in order to certify for 8800GTX in Sli. The M12-700 is excluded because it "only" has 56A on the 12V rails.

What the... according to Jonny too, the ToughPower 750W that is Dual 8800GTS certified can only output 48A on the +12V rails without dying.

Big deal if the total +12V is rated 60W.

The payment argument doesn't really have any relevance to this discussion, even if it were true. Why would Seasonic pay to get the M12-700 8800GTS Sli certified but then decide not to fork out for 8800GTX Sli certification?

Are Seasonic PSUs cheap (for their performance) or expensive? I can't tell from where I live, where prices are pretty mess up.

Coz if they're cheap, they'd have to cut costs somewhere right?

[nici]

Seasonic PSUs are not "cheap", but they are not overpriced either, like a lot of their competitors.. some of which use re branded Seasonic PSUs

[rpsgc]

180W TDP!? Wow! Where did you get that from?

The GTX8800 adapter card provides twice the performance of NVidia's current graphics adapter. It consumes 145W maximum and 116W on average. That compares to 116W max and 99W average on the last generation card.

http://www.eetasia.com/ART_8800441670_1 ... 611_no.HTM

[EsaT]

180W TDP!? Wow! Where did you get that from?

The GTX8800 adapter card provides twice the performance of NVidia's current graphics adapter. It consumes 145W maximum and 116W on average. That compares to 116W max and 99W average on the last generation card.

Quite a few reviews mentioned that little under 180W TDP for 8800GTX.

And if it's peak consumption would be under 150W there wouldn't be any need for two PCIe power connectors!

Also you can't take current max power consumption numbers as final truth, it's highly propable that with current DX9 applications putting G80 under 100% load is impossible.

[rpsgc]

And if it's peak consumption would be under 150W there wouldn't be any need for two PCIe power connectors!

Ever heard of standards compliance? PCI-E 2.0
http://www.pcisig.com/news_room/faqs/pcie2.0_faq/

[jaganath]

And if it's peak consumption would be under 150W there wouldn't be any need for two PCIe power connectors!

Ever heard of standards compliance? PCI-E 2.0
http://www.pcisig.com/news_room/faqs/pcie2.0_faq/

I may not be reading the spec correctly, but this:

PCI-SIG is developing a new specification to deliver increased power to the graphics card in the system. This new specification is an effort to extend the existing 150watt power supply for high-end graphics devices to 225/300watts. The PCI-SIG is developing some boundary conditions (e.g. chassis thermal, acoustics, air flow, mechanical, etc.) as requirements to address the delivery of additional power to high-end graphics cards through a modified connector. A new 2x4 pin connector supplies additional power in the 225/300w specification. These changes will deliver the additional power needed by high-end GPUs.

seems to suggest that max power draw is indeed higher than 150W.