Enermax EG701AX-VE/600Watt not cutting it in SLI?

[djt]

When I have SLI enabled on my AMD machine I get lock ups in games. I first blamed it on the PEG Link Mode settings. Now after playing around with it I’m starting to suspect the power supply. My video cards are consuming 280 Watts each and I don’t think my 600Watt power supply is cutting it. Its seems too do alright when the system is cool, but after playing one of my racing simulators for while it starts locking up in the menu screens. When the power supply is warm I suspect its putting out a lot less than 600Watt so I must be at the border line of minimum power requirements with these two video cards running in SLI mode.

I originally was going to buy a PC Power and Cooling 850SSI for this system but some told me that it was very noisy. I think its time to over look the noise for stability.

[Oklahoma Wolf]

My video cards are consuming 280 Watts each

That is highly unlikely - added together, both cards may approach that figure, but not each.

That said, Enermax units don't always meet their ratings. Yours is rated 18A+18A on the two 12v rails. If you're overclocking a Prescott or the video cards are presenting enough load, it might be possible it's giving up on you.

I'm not sure this is a PSU problem though - you mention there's no problem when the system is cool... I would check and be sure the vid cards and CPU are getting adequate cooling before going for a new PSU.

If you do end up needing a new PSU, I don't recommend the 850w. You don't need it. The 510w would be more than enough, as would be the Fortron/Sparkle FSP550-60PLG or OCZ PS520. The single 12v rail on these are less likely to run out of gas when extreme overclocking.

[djt]

Oklahoma Wolf,

This is where I’m getting the power figures from-
http://www.anandtech.com/video/showdoc.aspx?i=2494&p=5

The video cards are running hot to the touch, but I can’t tell if heat is the issue here. I’ve taken the side panel off my case and I still get lockups when playing certain games.

[Oklahoma Wolf]

This is where I’m getting the power figures from

That figure is total system draw at the AC outlet. Could also be a driver issue methinks.

[djt]

It’s the only thing that makes sense. When I turn the SLI off in the control panel and switch to the single video card settings in BIOS the problem goes away. It also seems to lock up more in “Alternate Frame Rendering” mode when SLI is enabled. I had the same problem with NVIDIA’s 77.77 drivers.

[Joeteck]

600 watts does not mean 600 watts. In my last post I was arguing about that fact the Dual 12V rails is the problem here..

Your 600Watt power supply has the same 12 volt rails as the Enermax 375Watt power supply.. Stinks right? Sure does!! Then how is your 600watts better?? Its not!!

Most of all of the high current items use 12 Volts. 18Amps is nothing... You have two power hungry video cards drawing around 100 watts each, easy...

Remember one 18A 12 volt rails is only for your CPU, and may be using only 7 amps, and your wasting the rest of the rail for nothing.. So technically, you only have one 12volt rail @ 18 amps... total output 216 watts for all of your hardware including your hard drives, RAM, mobo and optical drives. The power supply is your problem and always will be. Buy a beefy single 12volt rail such as the ENERMAX EG465P-VE(FC) and your problems will go away... I guarantee it!!
http://www.newegg.com/Product/Product.asp?Item=N82E16817103440

33Amps on the 12 volt rails!!! Good luck killing that!!

Joeteck

[Vulcan]

600 watts does not mean 600 watts. In my last post I was arguing about that fact the Dual 12V rails is the problem here..

Your 600Watt power supply has the same 12 volt rails as the Enermax 375Watt power supply.. Stinks right? Sure does!! Then how is your 600watts better?? Its not!!

Most of all of the high current items use 12 Volts. 18Amps is nothing... You have two power hungry video cards drawing around 100 watts each, easy...

Remember one 18A 12 volt rails is only for your CPU, and may be using only 7 amps, and your wasting the rest of the rail for nothing.. So technically, you only have one 12volt rail @ 18 amps... total output 216 watts for all of your hardware including your hard drives, RAM, mobo and optical drives. The power supply is your problem and always will be. Buy a beefy single 12volt rail such as the ENERMAX EG465P-VE(FC) and your problems will go away... I guarantee it!!
http://www.newegg.com/Product/Product.asp?Item=N82E16817103440

33Amps on the 12 volt rails!!! Good luck killing that!!

Joeteck

While I'm not a big fan of the whole dual rail idea, I wouldn't write off all dual 12v rail power supplies at once. Having a dual rail power supply is not a problem at all in my opinon.

This is my understanding of how the draw gets split between the rails.

12V1:
Hard Drives/Optical Drives
Video Card (through 6 pin PCIe Conectors or Molex)

12V2:
CPU
PCIe Power

I'm going to bet in a A64 / SLI system that the power draw is split pretty evenly (Probably around 5A/5A). Anyway, any power supply that can actualy provide around 15A on both rails will not give you a problem, atleast not in an A64 system.

You might want to check out this... http://www.silentpcreview.com/article265-page1.html

[Joeteck]

Incorrect! 12v2 is for CPU only....

Thats the problem.

AMD's don't draw nearly as much as a P4. So the 12v2 Amperage will never be over loaded... So now the entire system has to rely on the 12v1 @ 18Amps... This is very easy to hit with two cards in SLI.

Just wait. I sent off an idea to Enermax... Maybe we will see 3 12v rail power supplies soon with respectable Amps and each rail...

1 for video, 1 for CPU, 1 for mobo....

Joeteck

[djt]

Joeteck,Vulcan,

Thanks for the responses to my problem.

My way of thinking is that as the power supply gets warmer it puts out less and less total Wattage, am I correct in thinking this way? Anandtech says that these cards are drawing 280Watts each, although Oklahoma Wolf thinks they meant that this figure is total system draw at the AC outlet. If it is indeed 280Watts for each card and the power supply gets warm or hot I’m not going to be at 600Watts anymore. It seems to me that I’m border line right now even if I can stay at 600Watts when the power supply is cool.

It is only been recently that I have started to experiment with other power supplies. For the last four years or so I have only used PC Power and Cooling power supplies and never had one single problem. I started to try other makes because of the noise; I think I’m seeing that this was a mistake.

Although I know its total overkill for this machine, I talked to PC P&C today about the 1000Watt they are going to release shortly. It’s supposed to be even more efficient than the 850SSI. With there being only a fifty dollar price difference between the two, I might just go for the 1000Watt. At least I will be future proof and have a little peace of mind.

[Oklahoma Wolf]

Anandtech says that these cards are drawing 280Watts each, although Oklahoma Wolf thinks they meant that this figure is total system draw at the AC outlet.

We tested power load on the computer with the EVGA e-GeForce 7800GTX OC in the same way as the other 7800s that we've reviewed, and we found that this card is the most power-hungry. This didn't come as a surprise to us, given that both its core and memory clocks are higher than any of the others. As you can see, clocked at 490MHz, we see a power usage of 280 W; and overclocked at 500MHz, 284 W. For reference, the power load while the system was idle was 145 W.

Note the use of the words "computer" and "system" in this passage - they're referring to total system draw, I guarantee it. The PSU they tested with was the OCZ Powerstream 600w, a model known to have problems powering certain rigs due in part to its dual 12v topology - in many cases it has shown itself less capable than the 520w.

The 1kW and 850w PC P&C units are not necessary, and I stand by my prior recommendations.

[woodchuck69]

Anandtech says that these cards are drawing 280Watts each, although Oklahoma Wolf thinks they meant that this figure is total system draw at the AC outlet.


Here's a link with an easier level of reading comprehension:

http://www.anandtech.com/video/showdoc.aspx?i=2451&p=20

Edit: listen to the Wolf and get the 510SLI. If anything, your system is easier to drive than the older 6800GT Ultra SLI setups - and the 510 would run those like cake. The new ones run cool and quiet. They are also 10% off through the end of September.

[djt]

Oklahoma Wolf, woodchuck69,

Thanks again, I’m finally getting some useful responses to this problem after posting on a couple of different forums.

The only reason I did not get the 510SLI in the first place is a guy at PC Power and Cooling said under full load the 510SLI would be just as loud as an 850SSI and run hotter.

Do you really think with the system listed below, 510Watts is going to be enough?

[Oklahoma Wolf]

It'll do it, easily :)

[Joeteck]

Just stay away from the dual 12v rail power supplies, and you'll be fine... I had no idea my 6800 drew that many watts... And to think that my tiny, Enermax 430 watt power supply can do it... It has a single 24 Amp 12volt rail... 288Watts total. The new Enermax 465 has a 33Amp 12v rail. with a maximum of 396 watts. Good luck.

If you notice, the top of the line power supply maker PC Power and cooling, does not even make a Dual 12V rail supply... I'll let that sink in for a moment...

http://www.pcpowercooling.com/technology/power_usage/

[Vulcan]

Incorrect! 12v2 is for CPU only....

Thats the problem.

AMD's don't draw nearly as much as a P4. So the 12v2 Amperage will never be over loaded... So now the entire system has to rely on the 12v1 @ 18Amps... This is very easy to hit with two cards in SLI.

Just wait. I sent off an idea to Enermax... Maybe we will see 3 12v rail power supplies soon with respectable Amps and each rail...

1 for video, 1 for CPU, 1 for mobo....

Joeteck
Even if that is the case, your ideas about how much power a computer needs are still way off. The CPU is obviously going to be fine, 18A is fine for even a heavily overclocked P4. Now, How do you figure that 18A is not enough for the rest of the system?

[Joeteck]

Here is a reply from PCP&C. read from bottom to top... thanks!

Bob Roark - PCPower
<bob@pcpow.com> to me
More options Sep 13 (22 hours ago)
We Like 1 rail for the same reason you do. No Resrtrictions. Look for Intel
to drop the idea soon.

----- Original Message -----
From: "PC Power" <sales@pcpow.com>
To: <bob@pcpow.com>
Sent: Tuesday, September 13, 2005 8:10 AM
Subject: Comment from the PC Power website


> This is an automated message from pcpowercooling.com. Joeteck has sent in
the following comments:
>
> -------------------------------------------------
> I'm not a fan of the Dual 12v rails. I also see neither is PCP&C, which is
great. Can you post some Pro's and con's about the incorrect hype about
this. AS I'm a firm beliver of having a monster 12v rail rather than 2
smaller rails. Thanks.

[djt]

Thegreek wrote - “PCP&C 850 has split rails which is the reason I did not buy it.”

" I hope they change it.”


Is this true, the 850SSI has split rails but the 510SLI does not?

[Oklahoma Wolf]

Is this true, the 850SSI has split rails but the 510SLI does not?

4x18A, in accordance with SSI EPS specs.

For really big single 12v rail units more capable than the PC P&C 510w or Etasis EPAP-560, one must look for units like Zippy's PSL-6701P and its 45A 12v rail.

[Vulcan]

Here is a reply from PCP&C. read from bottom to top... thanks!

Bob Roark - PCPower
<bob@pcpow.com> to me
More options Sep 13 (22 hours ago)
We Like 1 rail for the same reason you do. No Resrtrictions. Look for Intel
to drop the idea soon.

----- Original Message -----
From: "PC Power" <sales@pcpow.com>
To: <bob@pcpow.com>
Sent: Tuesday, September 13, 2005 8:10 AM
Subject: Comment from the PC Power website


> This is an automated message from pcpowercooling.com. Joeteck has sent in
the following comments:
>
> -------------------------------------------------
> I'm not a fan of the Dual 12v rails. I also see neither is PCP&C, which is
great. Can you post some Pro's and con's about the incorrect hype about
this. AS I'm a firm beliver of having a monster 12v rail rather than 2
smaller rails. Thanks.

You never answered my question.

Even if that is the case, your ideas about how much power a computer needs are still way off. The CPU is obviously going to be fine, 18A is fine for even a heavily overclocked P4. Now, How do you figure that 18A is not enough for the rest of the system?

[djt]

I just got off the phone with PC Power and Cooling again. After talking to them it looks like it’s just a matter of whether or not I think the 850SSI is worth the added money for slightly quieter operation. The 510SLI runs around 34 decibels and the 850SSI runs at 30. The 1000Watt will run roughly around the same as the 850SSI as far as noise goes. Like he said the 510SLI is more than capable of running my setup.

[Oklahoma Wolf]

Like he said the 510SLI is more than capable of running my setup.

As is the Fortron/Sparkle FSP550-60PLG or OCZ 520w I mentioned earlier - they will run quieter as well than any of the high wattage PC P&C units. The OCZ unit isn't quite as known for reliability as the PC P&C units, however the Fortron is.

There are also several Zippy units easily able to run the system up to a monster 700w with a 45A 12v rail, but they'll not be quiet either being more a direct competitor to PC P&C.

[djt]

So is it safe to say that even though the 850SSI has spit 12v rails (4 of them), this does not make it less stable than the 510SLI? Would the 850SSI’s split rail setup cause instability when overclocking?

[Oklahoma Wolf]

Hard to say until more real world overclocking results are reported.

What I can say is that they're vast overkill for most systems, and unless you have a dual CPU rig at least one 12v rail will go completely unused (12v1 and 12v2 on these are for CPU1 and CPU2). I have no plans on recommending either the 850w or 1kw any time soon - they're just too expensive and too much overkill for 99% of the overclocking rigs out there. It would be bragging rights only at this point for most people.

[djt]

Oklahoma Wolf,

Thanks again for your input. I think I’m getting real close to just going for the 510SLI.

One question I still have after all this discussion about split 12v rail problems. If my Enermax problem is associated with the split 12v rail, how then would this affect SLI? My problem as I mentioned before goes away when SLI is disabled. If the video cards are on their own PCI Express leads then how can an overloaded 12v rail be affecting them?

[Oklahoma Wolf]

Both video cards are powered by 12v1 on your PSU, which also powers the hard drives. It is possible that's enough to overload 12v1, however it's also possible you got a marginal unit - that's happened before.

Your 12v2 should be fine - an A64 does not load down that rail by much at all - it takes a Prescott overclocked or a dual CPU rig to start flirting with 14A+ current draws.

[djt]

I just ordered a PC P&C 510SLI, I hope this solves my problems.

Now what do I do with this paper weight Enermax?