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HX1000W and 2x GeForce 295 SLI Quad?


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Hello everyone. I am new to this forum and recently finished my first build. I have a BFG Ge-Force 285 oc xe powered by Corsair hx1000w psu.


I am in the process of trading up to the Ge-Force 295, although BFG seems to be dragging their feet (it's been a month since they emailed me saying I qualify for the trade, we'll email you again with details).


Does the hx1000 have enough juice to run two of these cards in Quad SLI?. I figure one will be enough for now, but as tech marches ever onward, when my system starts falling behind, easy upgrades would be the processor, and another graphic card in SLI.


I have gone to the BFG site and they reccomend a 1250w psu to run 2x295's. I have read a review of the hx1000 stating that it is identical internally as a Thermaltake 1500w psu, the only difference being 2 additional virtual 12v rails.


Is anyone running 2 of these cards with the hx1000? Would the system have enough power to be stable? Or, should I stick with the 285 and add another 285 later when needed?


Thanks in advance for your advice/comments.


PS. if anyone has same setup as my rig, and wants to know my bios settings for my OC, let me know I'd be happy to post them.

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  • 2 weeks later...

hello. I have following setup and having some issues.


mobo: evga x58

cpu core i7 920 @ 3.8

12gb ram 1600mhz at 1.65v

quad sli gtx 295 BFG


2 dvd drives. 2 thermaltake orange pretty good case fans.

and 2 slow case fans.

all powered by corsair HX1000w PSU


well it all works great till i start overcloking my GPU's once i hit the 680mhz on the gpu core. the pc just shuts down while runing the vantage benchmark. I connected an aditional PSU to power the second gtx 295 and the harddrives. and the shutting down stopped. and i could overclock the GPU's up to 720mhz core.


Is my corsair defective?? I have seen videos of similar setups or with more power demanding hardware using the corsair and no mention of power issues.


I have the first GPU using the main pci-e connectors(the ones that are not modular 12v2). then the second GPU is using pci-e connectors coming from the Blue outputs 12v2 of the PSU.



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oh I just tryd again after posting since i saw the psu rail graph. I tryd again with cpu @ 3.3 GPU's at 720mhz and shut down just starting the vantage test.


then i moved the 2nd GPU to the 12v1 on the blue outputs of the PSU and tryd again. NO shutdown! amazing. Now I can say I am 100% satisfied with CORSAIR HX1000W psu. :cool:


One quick question to RamGuy or any of the support techs here. Am I on the limit of the PSU?? or can I still add some more stuff. for example. additional 9800gtx or gtx 280 for physx. and 2 aditional raptor 10k rpm HDD's?? :confused:



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  • Corsair Employees
If you use both sets of modular PCIE ports on the HX1000 instead of using the fixed + modular, can you duplicate the same issues? Also, with your previous configuration were there any problems when the cards were running at the default settings?
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ramguy, there was no problem while running at 3.3ghz on the core i7 and everything else on the 12v2 rail while gpus where stock speed. once I started Overcloking the GPU's the shutting down began. max core speed I could reach on the GPU was 680mhz without shutting down.


Now I changed the second GPU to the 12v1 blue outputs and i can overclock to the max my card can do stable. The first(main) GPU is still using the fixed pci-e connections.


You didnt answer my question. " Am I on the limit of the PSU?? or can I still add some more stuff. for example. additional 9800gtx or gtx 280 for physx. and 2 aditional raptor 10k rpm HDD's?? "


Im positive itll handle an extra 9800gtx least on the 12v2 rail since it was powering 2 gtx 295's on that rail, what not sure is if itll handle a 280/285gtx plus the added HDD's

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  • Corsair Employees
The PSU should handle that load with no problems, a HDD can pull about 20 watts maximum per drive. If you take the CPU overclock out of the equation can you still duplicate the same problems when overclocking the graphics cards?
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i didnt test that. but there should be no difference. the cpu Vcore is still the same as it was when at stock clocks.


but the problem is solved. by doing what i mentioned above(using rail 1 for

2nd gpu). Or are you thinking the PSU should be able to handle all the load on the 12v2 rail only?

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  • Corsair Employees
The PSU is designed to accommodate 3 video cards so the fact that the previous configuration gave you problems would tell me that there could be something else going on. Since the system is stable now, I would leave it as it is, but if you have any problems in the future please let us know.
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  • 4 weeks later...

Bob808, Ramguy and avioni ,

Just wanted to inform you that should work and is CERTIFIED to work are two different thing.



You said that you haven't tried underclocking (back to stock) your CPU b/c the voltage was the same. This DOES matter. vcore is the MAX voltage your CPU will draw depending on demand, and overclocking your CPU will draw more current than having it at stock.


eg at 2.666mhz and 1.3 Vcore, your CPU is drawing 130watts

at 4.000 and 1.3 Vcore, your CPU is drawing 195watts


A difference of 65 watts!




This is the formula that determines the WATTAGE DEMAND from the power supply, and is what governs all demand on all components of your system ESPECIALLY the video cards! I'd give putting the CPU at stock clock a try. It DOES matter. This is also the reason your CPU gets HOTTER under load than when setting idle, (why it's hotter when overclocking as well)


Frankly, I'm a bit dissappointed with Ram Guy's responses. There is some furthing information that is not being included here, manily that the 1000HX is not 2x 295 certified.


Just b/c the 1000HX is rated at 3xSLI doesn't mean it's reated at 3Xsli on all cards. IN FACT, visiting the nvidia SLIZONE page here:



NVIDIA has not certified the 1000HX for 3Xsli on the 2xx platform (260, 280 or 285), nor is it quad 295 certified. It appears on the 9800 3xsli drop down however.


This either means it failed certificiation, or it hasn't been tested. nVidia should also post a 'failed' list so that we could know for sure.


The gents at either nVidia or Corsair should be able to answer this question for you.


I was actually looking at picking this PSU up today, but am holding off now, mostly because I hate when my system mysteriouslly shuts down.


At 1000Watts, however, you'd think there'd be no issues, but I read a review once that said it was actually two 500watt psu's fused together.


Is this true?


If that were the case, then running the cpu/psu off of the psu leads would cause you to be running an i7, motherboard, ram, fans and gpu off of a single 500 watt supply, and running both GPU's from the mod plugs would be putting ~660 watts on a single 500watt supply. No win situation.


I believe the 295 idles at 190 and loads at 330

(numbers from here http://www.neoseeker.com/Articles/Hardware/Reviews/bfggtx295/14.html)


is it possible to run your config like this:


295 (1) 8pin from powersupply 6+2,

295(1) 6pin from modular

295(2) 8pin from modular

295(2) 6 pin from modular


or would that short out the power supply?



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  • Corsair Employees

Giz, it's true that our HX1000 is not officially certified by Nvidia to run dual GTX295 cards, however that was not the question that was asked. The question was whether or not the HX1000 would power his configuration and the answer is yes. Aviani originally had both GTX295 cards running on the 12v2 rail and once one of the cards was moved to the 12v1 the problems went away.


The HX1000 uses a dual 12v rail design, each 12v rail is rated at 40a so you could look at it as being two 500w PSUs, but that would not be totally accurate since there is still only one 3.3v and 5v rail. Nvidia rates the GTX295 to pull a maximum of 289 watts a piece (http://www.nvidia.com/object/product_geforce_gtx_295_us.html).


On 12v1 you would have a single GTX295, your CPU and motherboard. While the 12v2 would power the second GTX295 and your peripheral devices. I have personally seen some of our show systems in the past run very similar hardware configurations with highly overclocked CPUs with no problems at all, the HX1000 is very underrated when it comes to the wattage it can provide to your system.


You would want to hook up the fixed PCIE cables to the first video card and then use the 12v1 modular PCIE ports for the second card, leaving the second set of modular PCIE ports for a third card if you were to run tri-SLI.

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Do you have any insight as to why it's not listed on the nV page as a certified solution for 2x295 or 3x260/280/285?


I've got a 295 and an 8800 GT (physx), and am considering this PS (it's on sale for 199cad after rebates), but I am worried that i won't be able to run an OC (both video card and CPU) off one rail. I'd like to do this b/c I'd like to add a second 295 to the 12v2 rail eventually, but I am worried that running the 295, cpu and mb off of 12v1 is not enough.


Effectively my comment of a the PS being two 500's stands, I mean running 295 and CPU off a single 500W rail is probably exceeding 500W under load.


Although the card is rated at 289, the actual draw recorded by several outlets has been over 300.

364 @ Toms: http://www.tomshardware.com/reviews/geforce-gtx-295,2123-9.html

329 @ Neoseeker: http://www.neoseeker.com/Articles/Hardware/Reviews/bfggtx295/14.html

300.7 @ bittech; http://www.bit-tech.net/hardware/graphics/2009/01/08/nvidia-geforce-gtx-295-quad-sli-review/16


300 (recommended) by Guru3d:http://www.guru3d.com/article/geforce-gtx-295-review-bfg/5


All of which are reputable outlets.



Combine that with the overclock he's attemption (~190W) and you are close to max [rating] on 12v1 without powering ram and the rest of the motherboard (EPS, NB, SB). Regardless, I think his issues could very well be the power supply not being able to feed his setup.


For a real test, he should move one of the GPU's to 12v2, remove the second GPU and retest. Repeat with only the second GPU installed on 12v2 to ensure that there are now HW issues.


Now move the GPU to 12v1 and only test the system with the CPU O/V and GPU o/c all on 12v1 (nothing on v2, other than perpherials (Sata, IDE, fans). I'm guessing that 12v1 will be over stressed.


perhpaps some of the HX1000's can supply more than 500W on 12v1, but evidently his isn't. Maybe he can claim it's failing and exchange it for one that can.

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Trubritar has posted a video that has a power meter running during a vantage run. You can see that the power load hits close to 970 watts. I'd have to assume that this would be impossible to run off of a 500w/500w configuration.
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I understand the HX1000 has two 12V rails.


But the competitors (eg. ********) havd 6 12V rails.

Doesn't it makes HX1000 a better PS ?

I feel it is a bit strange that feel HX1000 has two 12 rails is a bad thing.


I think it depends on what you are looking for.


EG, OC'd CPU, and two high power video cards - If you can't fit two high powered devices on a single rail, then your configuration may suffer stability wise because any two of those devices will max out a rail. however if


I think for efficiency less rails are better, however for specific examples, it doesn't work well.


An important factor is how the power is distributed across those rails.

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  • 1 year later...

sorry to bring an old thread back to life (especially since the new ax line is out now), but I just wanted to express my satisfaction with the hx1000 (and all of my other corsair products).


I have been running a monster system, without any issues, for going on a year now.


I am running a core i7-920 overclocked to 4.33 Ghz on a EVGA classified 3xSli mainboard. 6 gb of Corsair Dominator 2000 Mhz ram. Quad-sli (ge-force 295x2) setup with a 240 physx card for a total of 5 gpu's. An Asus xonar essence gets the soundcard duty. The rig is watercooled and uses a swiftech 655 pump. Also powered by the hx1000 are the pioneer blu-ray drive, dvd drive, 4 hdd's (2x300gb raptors in raid and 2x1TB WD RE3s in raid) 2 intel x25 ssd's, a total of 13 fans (including the one in the psu), 6 channel fan controller, 3 cold cathode lights, and a multimedia Internal IR Receiver (with VFD screen).


Considering the serious overclock on the cpu and a mild oc on the gpu's, thats alot of stuff to be running off any power supply but my HX-1000 has been pulling it off going on a year now.


I have read all about the ax1200 psu and it sounds even more impressive ;)

I will be using that in my next extreme build.


Thanks Corsair and Ramguy for the outstanding products and customer service.

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