Hello good peoples,
This is my first post here, I am not experienced with building systems or truly tech-savvy like many of you here, but am experiencing a quandry that I hope someone can help me with.
 
I have just gotten a Dell Precision Workstation 490 with a 750w power supply (yes, I'm upgrading the ram), and ordered an EVGA GeForce GTX 460 1gb to upgrade from an old ATI FireGL card (that came with the system). I have not even fired up the machine as I am waiting for a dvi-i cable to be able to connect it to my monitor.
 
The issue that I have is that the power supply that came with the system (specs here) has only one 6-pin pci-e power supply cable, and the GTX 460 requires two. I found this thread in the 200 series area, and read it, however, I do not know what a 'dedicated +12v rail' is or if I even have one? The adapter that another poster mentioned is no longer available so I don't know what that was or if it even applies in my case. In the case that I do not have a dedicated rail, what are my actual options?
 
Being that I am on a rather low, fixed budget, getting a different power supply is financially not an viable option for me at the moment, so I am thinking that some kind of 'splitter' for the pci-e cable may be the way to go, since the power supply can more than adequately deal with the power needs of the card and other peripherals. I understand the hose and fire hydrant analogy, but is the idea of a splitter total nonsense or logical/semi-logical or even doable? (please be gentle with me  I'm new and trying really hard to understand and learn more)
 
I really need this card as it is CUDA ready and I use 3ds Max '12... so I bought this machine and am customising it for this particular purpose (and CS5 suite purposes as well). What can I do to make this work for me?
 
Any and all assistance is greatly and humbly appreciated and accepted.

Are you sure there is only 1 6 pin connector?
according to the specs for that power supply that I found there should be two. Not that it really matter as Dell chop and change their components to whatever they can find the cheapest all the time, plus looking at that link you are buying a second hand/refurbished product, so definitely do not expect much life out of that power supply.

Hi Kaninja, thank you very much for your reply.
 
The only cables that are not being used are two SATA connectors and one 6-pin PCI-E connector.
 
When you said "daisy chain"  do you mean using the splitter?

Hi Simba123, thank you for your reply.
I can see where the two 6-pin PCI-E connectors fit into the card itself, I just can't see where any molex (the 4-pin) would plug into anything? But I think I don't have anything to plug that end of the adapter into, actually.
 
And regarding the manufacturer's recommendations regarding power supply for this card:

Requirements
Minimum of a 450 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 24 Amps.) 
 Two available 6-pin PCI-E power dongles

 
Now, whether it can physically run on 18.0A is another matter :) Again, I'm not a gamer, just a modeler so I don't know if that makes any difference or not.
 
So that leaves me with two options (as I see it, and I may be wrong, being basically ignorant but trying to learn):
a) use a 6-pin PCI-E splitter and underpower it
b) get a different power supply unit
 
Trying to do some homework (and learn), I've looked at some PSUs that have the same amount of power (750w). Now, I know all you gamers would use a much better PSU, and I understand why, but these are what I can afford (not really, but c'est la guerre!) - child and I do have to eat the rest of the month  :
 
Diablotek PHD750 Power Supply - 750W, ATX, Black (new, 1-yr warranty)
slightly different, the 3.3V - 24A (current one is 30A), but the +12V is 21A (vs current one @ 18.0A) and the 5V is 25A (vs. 16.0A on current one) Not sure if this makes a big difference, i.e., would fry something resulting in me weeping and wailing and cursing a lot
 
Ultra Lifetime Series Pro 750W ATX12V & EPS12V Power Supply (new, lifetime warranty)
again, slightly different: +3.3v - 28A (vs 30A on current one), +5V - 32A (vs current on @ 16.0A), +12V1 - 45A (vs. 18.0A on current one), -12V - 0.6A (vs. 0.2A on current one) and finally +5VSB - 2A (vs the current 5VFP @ 3.0A)
I'm not sure what those differences are, specifically and if they would over or underpower anything and again fry stuff and cause me to weep and turn the air blue, causing more grey hairs on my head and child to start talking like Mommy does when she gets really mad
 
I'm looking at some other ones on NewEgg, even considering a 700W or even 650W, though if I can do the PCI-E splitter, we'll definitely eat better :D