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Enough power supply for HD7750?

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  • Power Supplies
  • Components
Last response: in Components
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May 8, 2013 3:37:54 AM

I have an older sff pc and recently upgraded everything inside including a new 275W psu from FSP that seems to be the best that would fit the unusual size of the old PSU.

BIOSTAR H61 itx motherboard
OCZ SSD
BLURAY drive
2×4 GB RAM
USB 3.0 front panel bracket
mouse
keyboard
USB WIFI adapter

I initially put a i5-3570k (stock speed) and attempted to add a HD7750.

The fan on the card spun but it would not boot with anything on the display nor did Windows find it once I switched the monitor cable back to the onboard option. I made sure in the BIOS that it looked for PCI-E before onboard but that didn't work either. I tried in my main machine and it worked fine.

It seemed it needed more power than the PSU was providing.

The PSU specs are here:
www.atxpowersupplies.com/275-watt-power-supply-FSP275-6...

I know that the HD7750 is supposed to need a 400w PSU but I figured a combined 22A on two +12V rails would cut it (8A on +12V1 and 14A on +12V2).

I figured 77W in CPU 75W max in GPU left 125W for everything else plus headroom.

I would really like to get a decent low end GPU into this. I'm thinking of trying again with a less hungry CPU, maybe even one of those "t" models with 35W power requirements.

Any thoughts?


More about : power supply hd7750

a c 144 ) Power supply
May 8, 2013 3:49:30 AM

Is your Case the AOpen XC Cube?
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a c 131 ) Power supply
May 8, 2013 3:50:31 AM

That PSU ought to be enough. Is the BIOS on that mobo up to date?
Which HD7750 is it? Are you using a DVI-VGA adapter? Make sure you're plugging it into a DVI-I port, not DVI-D; the latter carries only digital signals and can't be converted.
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May 8, 2013 4:10:48 AM

Yes it's an XC CUBE EZ18 enclosure

The BIOS was definitely up to date because I had to flash it to get the ivy bridge CPU to work.
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May 8, 2013 5:26:00 AM

I forgot to answer the other questions. I plugged into DVI directly and it was the HIS iCooler H775FS2G 2GB
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May 8, 2013 6:04:02 AM

I'm looking at a 55W i3-3220 and a PowerColor AX7750 1GB now. I'm hoping 22W less power for the CPU and only 1GB for the GPU may do the trick.
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May 14, 2013 8:21:26 AM

Here is an update:

I received the i3-3220 and the 1GB HD7750 and installed last night.

The i3-3220 works fine (including graphics). When I plugged in the HD7750, nothing on the screen (yes I switched the cable to video card). I tried to tweak settings in BIOS, but nothing worked, and the card was not recognized in Windows at all (nor by the Radeon Catalyst suite that I tried to install).

I figured the PSU was just too weak. I then plugged my OCZ 850W power supply (the one that runs my main machine). The card still did not show any sort of signal nor was it recognized by Windows as being "there".

I have concluded that the PCI-E or other component on the motherboard is likely bad. I'm going to do everything I can to get a replacement. I think the PSU is sufficient to run the card (the fan runs after all so it IS getting power somewhere), but somehow the card is not recognized by Windows.

I tweaked many settings in BIOS in case something would work. The last one was disabling the onboard video, which was a bad idea as the BIOS beep codes fired on the next boot since I have "no" video card installed. I will need to reset the BIOS to default settings and try and get a new motherboard.
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June 17, 2013 5:43:00 AM

Just to wrap up this thread - I ended up sending the motherboard back to Biostar. They sent it back as being "repaired" and I tried and still no video from the video card. They claimed they got a video signal when plugging in a video card but I could not.

I decided to take a gamble and ordered an ASUS H77 mini-itx board. It arrived last week and I installed everything last night. Video card works perfectly. I'm not sure if is the specific board that was wrong or something with the H61 chipset and/or BIOS and/or using Ivy Bridge processor (maybe the Biostar tech used a Sandy Bridge processor??), but the ASUS board works exactly as expected.
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a c 2488 ) Power supply
June 17, 2013 10:22:44 AM

ASUS is the right choice , I wouldn't ever purchase a Biostar board.Glad to hear you have a working unit.
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