When I purchased my Rage 128 (Which was released for the first time for powermacs), PC's got Radeon (Next Generation).
The Rage 128 for Mac was released in 1999 if I recall. Radeon (PC-side) made its debut in 2000 (April if I recall). The first Radeon for Mac? Released in 2000 (July/August).
When I purchased my Radeon9800, again, PC's had the next generation already.
Ah, when *you* purchased it =/= when it was released. Radeon 9700 Pro. Launched: August 2002
* Radeon 9700 Pro Mac Edition: Launched January 2003
* Radeon 9800 Pro (PC), Launched: March 2003
* Radeon 9800 Pro (Mac), Launched: July 2003
It would be roughly a year between the launch of the 9800 Pro for PC, and its successor generation, giving the release of the Mac version parity with the PC version for several months...
When I purchased X850XT, PC's had the 1800 series.
Once again, when *you* purchased.
* Radeon X850XT (PC), Launched: December 2004
* Radeon X850XT (Mac), Launched: January, 2005
* Radeon 1800 series (PC), Launched: October, 2005
Once again, that's a considerable amount of time of parity between the two...
So no. I think you are remembering incorrectly.
No, fairly certain you are...
And not having SLI/Crossfire hinders the possibility of having GTX295 like dualcore cards on macs.
Not true. Users on Mac Rumors even got the GTX 295 Co-op edition to work via driver hacks:
https://forums.macrumors.com/showthread.php?p=8199020#post8199020.
Since their drivers use the SLI technology even if they are not SLI in practice.
Ok, here's the thing: it would be fairly simple for nVidia and Apple to implement driver support for a card such as the GTX 295. The 295 (and prior dual-GPU nVidia cards) have SLI implemented as part of the PCIe switch that connects the two GPUs. There would be no need to support a chipset-level SLI solution, because that comes with far more complexities (supporting SLI via different GPU models, supporting the SLI chipsets themselves, etc.).
The GX2s and the 295 are SLI at their most basic level. Even Linux has support for the 295. It's really just a matter of Apple not caring enough about gaming (which, admittedly, gaming is a very small % of the market), and thus partners like nVidia and AMD not caring to push it much either.
So when the time comes when a mac can run a dualcore card, then a mac will be able to run SLI as well.
SLI can be implemented either via a single card solution, in which case it's very basic and requires nothing more than essentially supporting a dual GPU solution for a singular model, or it can be far more complex, involving a chipset-level solution integrated into the motherboard, a la the nForce chipsets, etc.
The chipset-level solution involves considerably more complexity, and I don't see Apple going towards that any time soon.
Supporting SLI for singular graphics cards however is not a big deal, and Apple should already be supporting it...