PSU upgrade for a Dell 490 to power a gtx770

Petersaurus

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Feb 20, 2014
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I have a dell 490 and the power supply it comes with is 750Watts.. however only has enough cables to supply the components that came in the unit.....I would like to put a Gigabyte GTX770 4GB in it....

It was powering a FX4800, but the GTX seems to need 2X 8 pin PCIe...and apart from the 6pin left by removing the FX4800 and a spare LP4 cable I don't have much else!

I don't really want to start buying adapters to start daisy chaining inside the unit so does anybody have any suggestions for PSU with ample cabelling to power this? (Or any other suggestions that may work with the exisitng PSU)

Thanks in advance!!

Pete
 
Solution
The Dell Precision 490 uses a dual CPU motherboard that has both a 24-pin ATX12V main connector for the primary CPU and a 20-pin ATX12V connector for the secondary CPU.

The server power supply that is originally used in the Dell Precision 490 has both a 24-pin and a 20-pin connector.

If two CPUs are installed you would think that both the 24-pin and 20-pin connectors should be connected to the power supply since there are no 4-pin or 8-pin CPU power connectors on that motherboard. Do you have two CPUs installed on that motherboard or only one?

The chipset on that motherboard only supports PCI Express Revision 1.0a so the GeForce GTX 770 will lose at least 6% of its performance due to the lower PCI Express bandwidth alone and that is...

Petersaurus

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Feb 20, 2014
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Cheers HiTechObsessed, Just noticed whilst taking the box apart there are two power cables for the mother board...a 24 and a 20 pin....the PSU you have suggested only has one 24 pin...you think its ok to just have a 24 plugged in? (dell power supply had both 20 and 24 cables and both were plugged in)

thanks again
 
The Dell Precision 490 uses a dual CPU motherboard that has both a 24-pin ATX12V main connector for the primary CPU and a 20-pin ATX12V connector for the secondary CPU.

The server power supply that is originally used in the Dell Precision 490 has both a 24-pin and a 20-pin connector.

If two CPUs are installed you would think that both the 24-pin and 20-pin connectors should be connected to the power supply since there are no 4-pin or 8-pin CPU power connectors on that motherboard. Do you have two CPUs installed on that motherboard or only one?

The chipset on that motherboard only supports PCI Express Revision 1.0a so the GeForce GTX 770 will lose at least 6% of its performance due to the lower PCI Express bandwidth alone and that is assuming that the GeForce GTX 770 will even run on that motherboard without compatibility problems.
 
Solution

Petersaurus

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Feb 20, 2014
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@HiTechObsessed - Was a surprise to me to...cable was well hidden! I think it it this motherboard - GU083

@ko888 Ah that makes sense...It does have two cpus...and actually as a test if I try and boot with the 20 not plugged in, nothing happens at all...so yes I think it is safe to say the both need to be in.

I got the GTX working....be it with a 6 - 8 pin PCIs adapter and sacrificing the power for the CD drive...and seems to work ok. Used 3dMARK and benched marked at around top 6000's.

But if you think that I may be loosing performance, perhaps I should look into a new mother board....this is turning into a full rebuild! I wanted to move the OS onto a SSD as well. Can't see any such adapters to get a 20pin working say from a few LP4s, for a newer PSU.
 

farner

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Feb 23, 2014
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Petersaurus - Im running a 490 and I'm trying to put in an XFX R7870 DD GHz edition. I didn't have the right power connectors, so I bought a P690 PSU (2 x 6-pin PCIe connectors - 750W). Even with that, I plugged the 7870 in and got a BIOS beep with no video feed. I plugged in my old GPU (the 490 doesn't have two 16x PCIe ports, but I had cut out the back of my 8x ports and had been using two GPUs before) and the BIOS was saying that there was an error initializing PCIe port 2 (the 16x w/ the 7870 in it).

What do you guys think the issue is? The 7870 ran fine in my friend's PC, and my friends 5970 ran fine in mine. I'm running two X5365 Quad-core 3.0 ghz processors, with 32 GB of RAM. Do you think it's a PSU issue? Too much power for the 750 W?