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Graphics card power connectors

Last response: in Graphics & Displays
March 31, 2011 8:14:18 PM

hi ....i would appreciate what is probably basic knowledge for some about the necessity of power connectors on a graphics card...if the psu is rated 575 watts and i am putting 2 quadro fx3500 in sli mode with 2 or 3 monitors in an hp xw 6400 comp is it necessary to have the connectors fitted and if so where exactly do they connect ....excuse my ignorance but on previous projects i ve just had to connect to the board ie pcie it to give extra power to the cooling fan?
March 31, 2011 8:19:02 PM

Higher end cards or what used to be higher end cards require more power than the average card, power they cant get through the motherboard. They will need the power connectors if you want them to work at all.
March 31, 2011 8:25:52 PM

i m running 2 quadro nvs 450 on another machine of the same specs and no extra power is needed for those ...was wondering if there was enough power on the rail to run each card
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March 31, 2011 8:32:50 PM

Your PSU should run it and the reason one will require connectors is just because it needs more power, maybe beacuse its more powerful or not as efficient as brand new cards.
March 31, 2011 8:38:54 PM

Your PSU will be sufficient for those cards provided that is a true power psu and not an old no name. You will need 2 six pin connectors or if the PSU does not have them you will need molex to six pin adapters in order to properly connect the video cards.
a c 540 U Graphics card
March 31, 2011 9:41:42 PM

Each NVIDIA Quadro FX 3500 graphics card has a Maximum Power Consumption of 85 Watts. That exceeds the the maximum power draw allowed for a PCI Express slot so a 6-pin PCI Express supplementary power connector is required for each graphics card.

The HP xw6400 motherboard wasn't designed to support SLI:
Slot 1 - PCI Express x16 @ x16 bandwidth
Slot 3 - PCI Express x16 @ x4 bandwidth

I doubt that an SLI bridge connector was included with the HP xw6400 which would confirm that SLI isn't supported.

The HP xw6400 power supply may only have one PCI Express x16 auxiliary connector on the +12V-D rail.
March 31, 2011 10:16:17 PM

thanks for the input i understand it then ,it won t be possible to have the 2 cards if this aux conn is required to run the card and there s only one present the way, as i mentioned previously i have already got sli config on an identical system with no bridge required....2 nvs 450 running 8 monitors ...the comp configured automatically an sli set up
March 31, 2011 10:28:19 PM

to add to my may also be that the dual dual processor xw6400 board was modified thus which happens to be what i have on both counts
April 1, 2011 9:27:24 AM

sli mode 8 lanes on each card