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 slot...is it to give extra power to the cooling fan?
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.
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.
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.
thanks for the input ko...as 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 ....by 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