PSU reccomendations

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humatrope

Junior Member
Apr 18, 2008
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I'm getting ready to build a new gaming pc and I need some help deciding what tpe of psu to buy. I don't want to get something inadequate. My system specs:

Cooler Master Stacker 830
XFX 780i motherboard
Intel E8400 3.0ghz proc (going to try and OC this to 4.0ghz on air)
4 gigs Corsair XMS2 DDR800 (probably up to 8gigs shortly)
BFG 640mhz 8800gts 512mb card x 2
Zalman 9700 heatsink
Windows Vista Ultimate 64 bit
120mm fans x 8
1 x DVD burner
1-2 7200rpm hard drives


I was thinking about this psu http://www.newegg.com/Product/...k=silverstone%2bst1200
but I'm not sure I need something that large and I'm worried about my circuit breaker being able to handle that type of load on it (I live in an Apartment).

I don't know that much about psu's and I've read conflicting articles about single and multiple +12v rails and which one is best. If I could get by with something in the 800-900 watt range, that would make me feel a little better about the load on the circuit breaker.

Thanks for any help you can provide as I'm really unsure of what to get.
 
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HOOfan 1

Platinum Member
Sep 2, 2007
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Well I dunno about trying dual 8800GTS with something as low as a 500W

anyway I would say a 600+Watt for Dual 8800GTS lower will work, but I personally like to have some head room...750 Watt sounds good for dual 9800GX2
 
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HOOfan 1

Platinum Member
Sep 2, 2007
2,337
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Originally posted by: humatrope
How does this psu look for dual 9800gx2's including the rest of my system?
Click to expand...

Which one the Silverstone Strider 1200?

Obviously it would be enough, but you could go with a smaller PSU also

If it were me, I would go with the new BFG ES-800 or perhaps the Coolermaster Real Power Pro 850 Watt.

BTW about your worries about your circuit breaker, the PSU will only pull as much power as it needs to pull. If the System only needs to pull 600 Watts which is probably the most your system would ever pull and your PSU is 80% efficient then it will only be pulling 750 Watts from the Wall whether you are using an 800 Watt PSU or a 1200 Watt PSU

Edit again: 750 Watts of AC power is only 3.5-7 Amps depending on what region you are in and what Voltage they provide (110-240V)
 
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MarcVenice

Moderator Emeritus <br>
Apr 2, 2007
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The silverstone 1200w looks good, modular too, which is nice. It should power 2 9800gx2's, although 2 9800gx2's often give worse framerates then a single 9800gx2. I'd rather TRI sli 3 9800gtx's.
 
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MarcVenice

Moderator Emeritus <br>
Apr 2, 2007
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Look at this chart: http://www.anandtech.com/video/showdoc.aspx?i=3275&p=7

You can see how 2 9800gx2's draw 660w of power. That's a little over 75% of the PSU's rated capability. A quality PSU will cope, for sure, but I'd feel more comfortable with 50% load. Hence I suggest you get a 1000-1200w PSU.

Still, I'd rather go with three 9800gtx's. That'll require 3x6pin and 3x8pin pci-e connectors, not something many PSU's have...
 
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humatrope

Junior Member
Apr 18, 2008
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Thanks for all the information.

I think I've decided to stick with the Silverstone Strider 1200 since all of its cables are 100% modular.

I'm not going to quad sli 9800gx2's anytime soon (but want a psu capable of it in case) and may just wait for the 9900 series cards to come out.

I just want to get myself a nice psu that will be able to handle what's coming in the future (for a short time anyway), get my new sli 8800gts vista ultimate 64 bit system built and then I'll worry about upgrading down the road.

HOOfan1's comment about a 1200 watt psu and breaker overload makes me feel a little better as well.

Is there a suggestion of a psu that has the 3x6 pin and 3x8 pin pci-e connectors. I notice the Strider 1200 watt psu has 6x6 pin and 2x8 pin pci-e connectors.

By the time I'm ready to go tri-sli, I'll have to upgrade to the 790i motherboard, ddr3 memory, and Quad core 45nm Intel chip.
 
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HOOfan 1

Platinum Member
Sep 2, 2007
2,337
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Originally posted by: MarcVenice
Look at this chart: http://www.anandtech.com/video/showdoc.aspx?i=3275&p=7

You can see how 2 9800gx2's draw 660w of power. That's a little over 75% of the PSU's rated capability. A quality PSU will cope, for sure, but I'd feel more comfortable with 50% load. Hence I suggest you get a 1000-1200w PSU.

Still, I'd rather go with three 9800gtx's. That'll require 3x6pin and 3x8pin pci-e connectors, not something many PSU's have...
Click to expand...

Well I am sure that is 660W from the wall...not to mention that Kil-A-Watt type meters are not always accurate, if the PSU is 80% efficient then 660 Watts from the wall is 528 Watts of actual DC output. That would only be 62% of max load.

Edit: I just checked SLI-ZOne and the Zalman ZM850-HP is certified for dual 9800GX2....and you can be sure that nVidia is very conservative when certifying for SLI

Edit again: The 9800GTX has 2 6pin PCI-E so triple 9800GTX wouldn't require any 8 pin connectors, but 6X 6 pin connectors
 
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MarcVenice

Moderator Emeritus <br>
Apr 2, 2007
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I don't think AT uses a kill-a-wat to measure load/idle power draws though? If the zalman is certified then it'll work, would I be comfortable with it, not sure ... If it is 528w, then I probably would be. Not sure why I was thinking 1 6pin and 1 8pin, perhaps thats for the 9800gx2 ?
 
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HOOfan 1

Platinum Member
Sep 2, 2007
2,337
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Originally posted by: MarcVenice
I don't think AT uses a kill-a-wat to measure load/idle power draws though? If the zalman is certified then it'll work, would I be comfortable with it, not sure ... If it is 528w, then I probably would be. Not sure why I was thinking 1 6pin and 1 8pin, perhaps thats for the 9800gx2 ?
Click to expand...

I just looked at the article again and the test system they are using is a Skulltrail with 2X QX9775. So I think you can attribute at least 70-80Watts to that second CPU.

Also I am sure they are measuring AC input and not DC output.
 
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MarcVenice

Moderator Emeritus <br>
Apr 2, 2007
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Wow, I'm getting sloppy, you're right. 2 QX9775 and fbdimms ain't exactly powerfriendly components. The zalman should indeed be just fine.
 
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humatrope

Junior Member
Apr 18, 2008
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This a sight I just found that has a list of approved cards that will work with 1 9800gx2 and it lists power supplies total number of 6 and 8 pins on them. This is directed at MarcVenice an the statement he told me earlier. If I want to somewhat futureproof myself at least on a psu, that I need something that has a good number of 6pin and 8 pin connectors.

http://www.nvidia.com/object/g...800gx2_pwr_supply.html
 
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humatrope

Junior Member
Apr 18, 2008
9
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What is the difference in these two psu's

This one http://thermaltakeusa.com/prod...hPower/w0216/w0216.asp is listed on slizone as compatible with dual 9800gx2's, this is not listed http://thermaltakeusa.com/prod...hPower/W0133/w0133.asp

Both are listed on Thermaltake's website as quad sli certified.

I've decided that I'm going to buy ones of these 2 units since they both have 3x6pin and 3x8 pin pci-e connectors. I may have to return my Cooler Master Stacker 830 as this psu is 7.8" long and will only leave about 2" from the back of the psu and top fan bracket.
 
jonnyGURU

jonnyGURU

Moderator <BR> Power Supplies
Moderator
Oct 30, 1999
11,815
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Originally posted by: humatrope
What is the difference in these two psu's

This one http://thermaltakeusa.com/prod...hPower/w0216/w0216.asp is listed on slizone as compatible with dual 9800gx2's, this is not listed http://thermaltakeusa.com/prod...hPower/W0133/w0133.asp

Both are listed on Thermaltake's website as quad sli certified.
Click to expand...

Spec-wise, they're both the same. So my guess is that they "corrected" something with the 0133 to come up with the 0216. Since they're both Quad SLI certified, but only the 0216 is 9800 GX2 certified, I'm willing to be it's the position of the clip on the 6+2-pin so it fits into the 9800 GX2's restrictive housing.


 
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