2 GPU's in sli and then in non sli, what work do they do?

2 Nvidia 6800XTs and 1 BFG PhySx Card onboard an ASUS M2N32SLI Mobo.... Athlon X2 64 4400 running at 2.5GHz, 4GB PC6400DDR2 and infinite Sata Space..... ok Running Vista 64bit for the past 3 years now... no hiccups..... until now...... In SLI ON config..... one card heats up to an extreme shutting down the system during gaming...... finally removed the second card from the mobo all together..... Simple question.... How is this going to effect the gaming performance.... since the single card suffices most gaming requirements all though newer ones on low resolutions..... secondly.... I was hoping to know suppose I was to put the second gpu back in..... but remove the SLI cable and have it running..... is it going to be like an added piece of hardware of no use or is it going to do some work sitting in it's place ?
If you remove the SLi bridge and SLi remains enabled in the Nv control panel then you have one of the setups that I've heard and read about but never seen, SLI without the bridge. If SLi does remain disabled without the bridge the card will only be of use if you have a monitor or two plugged into it otherwise it will just be there using power and creating heat for no reason whatsoever.

I removed the Card first:
Result: Temp dropped by 10Degrees...... Massive change....
Was still able to play Mirror Edge..... Undercover etc etc
After That I put in the second Card..... No Bridge to connect them....
Temp of both the cards is touching 64 degrees Cent. That's 10 degrees higher than just when running a single card
No noticeable change in any of the games above....
Yup In the NV CPL SLI is still enabled......

So what do you say?
Is it worth wasting the power and adding to the Heat level of the world by running two cards??? Or should I stick to one.... until I get a game I want to play and it tells me to shove another card in?
Another thing.... the BFG Physx I'm using does fire up a lot ...... what do you suggest I ought to do.... the Fan that came with burnt and melted away within 3 days of me buying that card..... ever since then I've glued a P3 In the Box Processor fan into the heat sink..... it seems to be working fine for the past 4 years now..... dunno..... do they have a cooling kit of this card..... or is it going to be redundant after I get myself the GTX295's?
If you cannot see or feel a difference between a single card and SLi then why run it? same goes for the physx card and your GTX295's, try it with and without and if you don't see or feel a difference then what's the point?
Truely... I agree with what you say...... but the green sli indicators do have a charm of their own....... lol
Although the only visible difference in running cards in SLI and Non Sli ways is seen thru my 3D Marks program...... just a difference about 700 points... 2862 3DMarks With SLI and 2182 3DMarks Non SLI Single GPU running at 470MHz OCed....
As far as the Physx card goes.... Yes, presently I do see the difference when gaming no doubt about that . But I believe, the GTX295's come with an on-board Physx chip , since Nvidia took over Ageia...... I was wondering , since the write ups and reviews happen to tell me that in 2 or 3 SLI setups..... one is dedicated to calculating the physics of the game and the other is used for graphic calculations..... but since I already have a separate Physx unit..... I wonder if I will be able to balance the load of the graphics on just the two 295's and let Ageia handle the Physx bits.....
It does not have a separate chip on board, the GPU or CPU will be doing the the work and as such if you have a physx card you should be able to dedicate that to do the physx and let the GPU's just do graphics. If you are not running them already try the 191.03 or 191.07 drivers and run a few things with the physx indicator enabled to get an idea of what piece of hardware is being used i.e CPU, GPU or PPU.
If you haven't ordered the 295's yet then I would hold off or try and change to a single 275 given the CPU that you are using as I think you may run into the infamous CPU 'bottleneck' issue even at a resolution of 19 x10 if you go down the dual 295 route.
Oh Ok.... but I just ordered a whole new set of stuff..... which is
EVGA X58 SLI LE Barebone Kit - Intel Core i7 920 2.66GHz, 6GB DDR3-1333 Patriot, 1TB Hitachi
HDD, Full Tower ATX Case, 750 Watt PSU
plus EVGA P55 FTW SLI Motherboard - Intel P55, Socket LGA1156, SLI+PhysX, Crossfire
plus 2 XFX Radeon HD 4870 Video Card - 1024MB GDDR5, PCI Express 2.0 x16, CrossFireX Ready, (Dual
Link) Dual DVI, HDTV
and sorry not 295's but 285's

OK, I'm confused. Why would you order a socket 1366 CPU and a socket 1156 motherboard?
Lol..... yes it does sometimes help to have a few rich friends who buy stuff they see and like the wrappings of not knowing what they actually do and whether or not accessories for the same stuff is available or not.....:) happens rarely in life but it does...... Thank the lord......