Dual link? SLI multi-head?

Question

Hi all.
A couple of quick technical questions. I own an IBM T221(9503)-DG5 monitor, which can be driven from a dual link DVI connector (plus a single link one).
The NX6800GT-T2D256E is listed as having dual link support (in the chipset on the main page, and I believe there's a PDF which claims it too). However, I know there's been some confusion in the past - I understand that nVidia's reference 6800 boards really did have dual link (two SiI178s per output) connectors, but that these have been left out by all consumer manufacturers so far, and some other nVidia board manufacturers (e.g. Innovision) are still claiming dual-link support despite the fact that their cards provide two single link outputs. On the other hand, it's promising that none of MSI's other cards are listed as having dual link support.
Can anyone confirm for me that this MSI board really *does* have dual-link support on at least one of its heads? Currently the only boards with this feature are workstation class (Quadros, FireGLs, Realizms, etc.) and the Apple DDL boards (the 30" cinema display also needs a dual link connector). Since I've no need for the other features of workstation boards, I don't really want to pay that kind of money for a part which is different only in some $30 interface chips... so I'll buy the MSI part like a shot if the support is there. MSI UK haven't yet been able to confirm with head office for me.
Corollary: if there's an impending 6800Ultra version with the same connectors, I'll gladly wait for that instead!
In a related topic, as noted above my monitor is best driven from two DVI outputs (one dual link, one single). However, I've heard a rumour that SLI is only supported on one head - I know it disables the output from one card, but this is more restrictive. In my case, both heads are driving the same display, so in theory the driver ought to be able to cope by treating both outputs as one frame buffer... but can anyone give me details on the behaviour I can expect? If I have to switch to driving from a single head, there's little benefit to me from trying to run an SLI system - at that would lean me even more towards a 6800Ultra, if one is in the pipeline.
I'll need to buy a PCI-E system in which to put the MSI card, so I'm keen to be sure of myself before ordering even if I could return the MSI card should it not work as advertised.
Thanks in advance for any information.
Andrew Garrard
Prospective system:
Tyan 2895 (dual Opteron SLI)
MSI NX6800GT-T2D256E (x2?)
Current system:
Rioworks HDAMB (dual Opteron AGP)
3Dlabs VP990
PCI FX5200 (256Mb)
512Mb RAM
XP Pro
T221-DG5 (off the VP990, 2x single-link)
Iiyama VMPro 454 (off the FX5200)
Tagan 480W PSU
That's probably about all that's relevant...
Oh, and based in the UK.

Answer 1

Since I found out the answer to my own question...
The PCI-E 6800GT (OEM version of the NX6800GT-T2D256E) which I've got *really is* dual link - I can drive 3840x2400 at 25Hz from a single head, and there appear to be two SiI178s on board. Big hand to MSI. This presumably means that the board would be capable of driving Apple 30" cinema displays, although reports from people with Quadros suggest that the Apple display is a bit temperamental.
Unfortunately, I've had trouble getting the single link head to run 1216x2400 at 48Hz, so I've not got the whole display running at 48Hz yet, but I'm told that may be an issue with newer drivers so I'll try again (or play with PowerStrip). There's always quad head mode if I give up on SLi...
A word of warning: the second head on this card is DVI-D only - that is, it's a DVI-I connector, but with no analogue pins connected, so you can't use a DVI/SVGA adaptor to plug in an analogue monitor except on the primary head. That means that if you want a 30" Apple plus a CRT, budget for a second card...
I'm waiting on a new motherboard before I can answer my SLi question, but I can live with the options I've got even if I don't quite manage everything I'd hoped for.
Andrew Garrard