Hi all,

I'm new to the forums, and new to this whole endeavour so please be gentle with me... I'm trying to relive my youth, albeit with a budget that I couldn't afford now if these parts were all current and new, and build a gaming machine the likes of which I could only have imagined back in the day...

The Plan
Over the last month or so I've started to accumulate parts to make what I hope would become the most ridiculous/brilliant but functional Windows XP based gaming machine. I did a fair bit of reading and decided that I wanted to base my build around a Quad-SLI setup using GTX 780 TI's. I understand that these were the last cards to have official driver support within XP, supported Quad-SLI and were relatively affordable and easy to come by. I also understand that SLI is poorly supported and rarely offers any advantages, certainly beyond 2-way in most cases. None the less the whole point was to go over the top just because I can.

The next issue I had was finding a Quad-SLI supporting motherboard with XP driver support. A brief dalliance with an Asus Rampage III Extreme (misunderstanding that despite the four PCIx16 slots, it only supported Triple-SLI), and I found an excellent deal on the newer equivalent.

The Build
I've constructed my machine comprised of the following parts, and thanks to the truly superb "Snappy Driver Installer" I'm pleased to say that Device Manager shows that all hardware is installed and working as it should, despite Asus not offering official XP support on this board...

Asus Rampage IV Black Edition X79 Motherboard
Intel i7-4960X CPU
Be Quiet! Dark Rock 4 Cooler + Silent Wings 3 Fan
4 x 2GB Corsair Dominator Platinum 1600Mhz DDR3 (Obviously only <4GB is recognised by XP, but at least it's setup as Quad channel)
2TB Firecuda SSHD
EVGA 1600W Platinum PSU
6 x Corsair LL120 Fans (3 front intake, 2 top exhaust, 1 rear exhaust)
2 x Corsair AF140 Fans (bottom intake)[/list][/list]

So far I've installed just two 780 TI's to get it running, including using the Asus ROG Flexible SLI Bridge that came with the motherboard and was still sealed in it's packaging. I have a 3rd card ready, and am still on the hunt for the 4th at the right price. All are matching MSI GamingX 3GB models.

The whole machine is housed within a Corsair Carbide Air 740 High Air-Flow Case, which to my mind looks awesome, if not at all period correct.

Windows XP (32-bit) is installed successfully using IDE mode on the SATA Controller and Easy2Boot to do the installation itself. I was pleasantly surprised to find that it was still able to connect to Windows Update services too, so after a busy few hours of downloading the installation is also fully patched as far as it will go.

In terms of other software, I've only installed MSI Afterburner (no changes to settings as yet, just useful for monitoring) and "WinCDEmu" to mount ISO's when needed.

The PC is working nicely, boots relatively fast and seems to run smoothly. I've had no issues at all, no crashes, although only briefly ran one game for 5 minutes as a test.

The Problem
I have just one issue that I'm hoping more seasoned professionals can help me with, but I fear that it's a big one.

I have successfully installed the NVidia drivers for this card/OS combination (368.81), and it appears to have installed correctly. Both cards are seen in Device Manager, MSI Afterburner and the NVidia Control Panel.
However, that same control panel does not show me the option to enable SLI. It's missing completely - no mention of SLI anywhere at all.

This is my first SLI build so I have no prior experience, but it's clear from what I can find easily online that there should be a menu option to enable/disable SLI which should just automatically show up at this stage, but it just doesn't.

All PCI Slots are enabled, set to "Gen3" in the BIOS. The GPU's are installed in slots 1 & 4 as directed by the manual for 2-way SLI. Both slots are operating in x16 mode as far as I can tell.

My thoughts as to possible causes, none of which are particularly good:

Could using the 32-bit version of XP be a problem?
Despite the successful installation of all drivers, is XP just incompatible with X79?
Is something missing that device manager can't see at all, that is required for SLI to work?
Could be a BIOS setting that I've not seen that could affect SLI?
Seems unlikely but I guess my SLI Bridge could be faulty...

Can any of you wonderful people offer any suggestions as to what the problem might be?

In the absence of any other ideas my backup plan is to temporarily swap out the HDD with another and do a quick Windows 10 setup to see if SLI will detect properly then with newer drivers, which would at least eliminate any hardware issues...

The Solution?
I look forward to hearing from your collective wisdom, and thanks in advance for any help you can offer 😀