I'm currently trying to get my Southbridge Nforce 750a chip (on my ASUS M4N75TD motherboard) to jive with my 2 GTX 470s for a Hybrid-SLI setup.
I see the chip displayed under "Set SLI and PhysX configuration" in the Nvidia Control Panel, though when I play any sort of game, I don't see the chip being used when monitoring it with EVGA Precision. Both GTX470s show activity, dancing around 20% to 80% of GPU usage, but I always see 0% GPU usage on the northbridge chip.
Plus I don't get a "Hybrid SLI" icon in my taskbar.
Not to mention that my PC occasionally Blue Screens on bootup with the Southbridge enabled, and I would have to occasionally deactivate it and reactivate it to get it working properly again.
Why are you trying to get a crappy IGP to try to work along side two good GPUs? It doesnt have anything it can add to the performance, if anything it might drop performance a bit as there is some more overhead to feed another GPU. I doubt hybrid SLI is enabled for anything above a GT 440, everything from that point up is so much more powerful that it cant really help out at all.
The solution to your crashing issue and it not showing up as being used, do standard things with standard parts, if you attempt to get non standard behavior(aka Hybrid SLI with 2 good cards and a crap IGP) expect non standard behavior and instability.
Yeah, bad idea just enjoy great performance from 470 sli, the igp will add nothing even if you just had a single gpu. Furthermore it generally only works with low end htpc cards from what I remember but either way not worth doing imo.
As far as the blue screens go it is likely a problem with the hybrid SLI but it makes me wonder; what is the make and model of your psu and your complete system specs?
Yeah, I never had the blue screens until after updating my Bios, lately I've just been keeping the "Hybrid SLI support" option disabled to avoid the annoyance of tweaking with it further to get it working again.
Oh, and I did do some research on the side, the latest news or update I found on the topic was back in 2008, and they listed the 9800GTX and the 9800GX2 as the two only comparable cards. Anything newer beyond that seems that remotely bears the topic of "Hybrid SLI" applies only to Laptops.
But if you are curious about system specs,
Windows 7 Ultimate, 64bit
Kingwin Mach-1 1220 Watt PSU
2X EVGA GTX 470s in SLI
ASUS M4N75TD Motherboard with NForce 750a Southbridge
AMD Phenom II X6, 3.2 GHz CPU
6 GBs of RAM, DDR3 1333
4 Hard Drives, with Intel 80GB SSD for Operating System
Okay, found some benchmarks online that showed that Hybrid SLI did indeed drop performance a smidge like 10 to 28 frames per second or so, depending on which game you played, but the benchmarks also focused on power consumption as well in which it did indeed decrease power consumption.
In which case, with all the trouble I've been getting with Hybrid SLI, I'm better off without it. But thanks for your input, everyone!