Actually, Bert has the concept of efficiency and power ratings backwards. A 500W PSU should be able to supply 500W of sustained DC load. If it has a 80% efficiency at full load, it will be drawing 625W AC.
All of this is what the power supplies should be able to handle. The sad truth is that many PSU manufacturers tend to overstate their actual power capabilities or simply don't stress test their units properly.
That all being said, you don't want to be running your PSU at it's full capacity all the time anyways. It'd be like redlining your car continuously and expecting it to work after 3 months.
The 750TX should be able to handle the two 5850's you have with some headroom to spare. I'd check the actual power draw using a Kill-a-watt, and then estimate or look up the efficiency to determine the DC draw on the PSU. A safe estimate would be that between 30-70% load, the PSU would be 80% efficient. Otherwise, count for 75%.
The only two websites that I really trust for PSU recommendations are SilentPCReview and Jonny Guru. Both have the methodology to properly test power supplies to their full capability. (I'm a little biased in this regard since I used to work for SPCR).
Topic: Power Supply Question (Read 3404 times)
Asus M4A79T Deluxe 790FX AM3 ATX
AMD Sempron 140 1x 2.70GHz
2GB (1x 2048MB) Kingston ValueRAM DDR3-1333
250GB Samsung Spinpoint F3 HD253GJ 7.200
USB Wlan Stick
2x 120mm Fans
AMD Sempron 140 1x 2.70GHz
2GB (1x 2048MB) Kingston ValueRAM DDR3-1333
250GB Samsung Spinpoint F3 HD253GJ 7.200
USB Wlan Stick
2x 120mm Fans
What is your motherboard, CPU, RAM, HDD, anything else plugged into the machine USB devices (HDD,fans,???) ?
blew up my cheap PSU 
...
will the
Corsair CMPSU-750TXV2
(750, bronze, +12V 62A, +3,3V 30A, +5V 30A, +5Vsb 3A, -12V 0,8A)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021&Tpk=CMPSU-750TXV2
be fine with 2x 5850 + 140 sempron etc. ?
... will the
Corsair CMPSU-750TXV2
(750, bronze, +12V 62A, +3,3V 30A, +5V 30A, +5Vsb 3A, -12V 0,8A)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021&Tpk=CMPSU-750TXV2
be fine with 2x 5850 + 140 sempron etc. ?
Try to keep the temperature under 85 °C. After that ...
Allright! Well, thanks again tho! I will send you something when I made my first btc
Sorry, under UNIX I could write you a script, but I have no idea under Windows. Hopefully someone else knows the answer.
Was used, yes.
I plugged in the pcie cable for 2nd card, seems to work now (fans for both cards)... don`t why
Thanks again! Do you know any software that shuts down my pc if the GPU! temp gets to xx?
*edit* the temp was at 99+ so I guess I was pretty lucky that I monitored that right away.
I plugged in the pcie cable for 2nd card, seems to work now (fans for both cards)... don`t why
Thanks again! Do you know any software that shuts down my pc if the GPU! temp gets to xx?
*edit* the temp was at 99+ so I guess I was pretty lucky that I monitored that right away.
Is is being used when it is not spinning ?
Because the fans by default are set to auto, and if the GPU/VRAM/MOSFET's are not being used then the fan will spin down because the temperature will say that there is no need for cooling.
Because the fans by default are set to auto, and if the GPU/VRAM/MOSFET's are not being used then the fan will spin down because the temperature will say that there is no need for cooling.
Bert you`re great! Both cards are usable now
But there is another problem now :/ the fan of the 2nd card isn`t spinning or only slow, than stops... any idea?!
But there is another problem now :/ the fan of the 2nd card isn`t spinning or only slow, than stops... any idea?!
That really depends on the BIOS, the BIOS settings and type of video cable, VGA - probably, DVI - maybe, HDMI - probably not.
Thanks Bert!
I will try out to deinstall my drivers, put my dummy in, restart and reinstall them, just a min.
But still, shouldn`t I get a signal when I turn the pc off, plug the monitor in the 2nd card an start the pc?! Even if it`s not activated in windows, it should show me the bios loading screen etc, right?! (as I said, fan is spinning)
I will try out to deinstall my drivers, put my dummy in, restart and reinstall them, just a min.
But still, shouldn`t I get a signal when I turn the pc off, plug the monitor in the 2nd card an start the pc?! Even if it`s not activated in windows, it should show me the bios loading screen etc, right?! (as I said, fan is spinning)
Yea, but 6970 draw from 220 to 360 watts depending on (over/under)clocking and load. Call it 250W with no over/underclocking (it draws 174W when idle).
3 x 250W is 750W and most PSU's are 90% efficent so an 850W PSU can only supply about 765W. Allowing 50-100watts for CPU/RAM/motherboard/HDD/USB and you can see the problem.
EDIT: Sorry I was looking at the wrong graphics card
The 6970 each draw from 323W to 423W, straight away there is an issue trying to power 2+ of them from an 850W (765) PSU.
3 x 250W is 750W and most PSU's are 90% efficent so an 850W PSU can only supply about 765W. Allowing 50-100watts for CPU/RAM/motherboard/HDD/USB and you can see the problem.
EDIT: Sorry I was looking at the wrong graphics card
The 6970 each draw from 323W to 423W, straight away there is an issue trying to power 2+ of them from an 850W (765) PSU.
From the 1st link I gave above http://blog.zorinaq.com/?e=11 - "It made sense for drivers to not enable a GPU when no monitor was attached to it. But since the rise of GPGPU applications, graphics vendors AMD and NVIDIA realized that this behavior was inconvenient. At least with the most recent Linux drivers, dummy plugs are not necessary anymore. [Update 2011-02-22: However Windows still requires dummy plugs, as of February 2011.]"
Try downloading whichever of the below are appropriate for your Windows OS. Leave dummy in place, install, reboot, see if the 2nd card is visible.
http://developer.amd.com/sdks/AMDAPPSDK/downloads/Pages/default.aspx AMD-APP-SDK-v2.4-Windows-64 or AMD-APP-SDK-v2.4-Windows-32
Try downloading whichever of the below are appropriate for your Windows OS. Leave dummy in place, install, reboot, see if the 2nd card is visible.
http://developer.amd.com/sdks/AMDAPPSDK/downloads/Pages/default.aspx AMD-APP-SDK-v2.4-Windows-64 or AMD-APP-SDK-v2.4-Windows-32
but since the card that uses the two adapters shows no signal even if it is connected to the monitor, it must be something wrong with the power.
I am using a "gate" like this
http://www.sklep.soft-pc.pl/galerie/a/adapter-molex-molex-fdd_12186.jpg
well.. it comes directly from my PSU but "splits" in two molex. maybe this cable has only power for one pcie adapter but not the two?!
I am using a "gate" like this
http://www.sklep.soft-pc.pl/galerie/a/adapter-molex-molex-fdd_12186.jpg
well.. it comes directly from my PSU but "splits" in two molex. maybe this cable has only power for one pcie adapter but not the two?!
i installed the driver wenn I got my 1st card.
then equipped the 2nd one + used the adapter.
the 2nd card is exactly the same, should use the drivers from the first one, or what do you mean?!
then equipped the 2nd one + used the adapter.
the 2nd card is exactly the same, should use the drivers from the first one, or what do you mean?!
huh since you will runn this pc all the time buy only a brand psu and go for 80+and use this to calculate http://extreme.outervision.com/psucalculatorlite.jsp
cool link.. thanks for that
Did you install the driver with the dummy connected ?
yep, got a dummy right here.
the problem is... if I connect my monitor with the card that is powered by 2 adapters (and not 1 adapter + the 6pin pcie), I don`t get a signal. so my guess is that there is a problem with the power.
the problem is... if I connect my monitor with the card that is powered by 2 adapters (and not 1 adapter + the 6pin pcie), I don`t get a signal. so my guess is that there is a problem with the power.
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