So I finally got around to re-installing Windows, stuck with W7 cause I'm a luddite
Did some upgrades though, and found out that W7 Home Premium only supports 16Gb RAM, and I'd just upgraded by adding 16Gb (to 8Gb), what's worse is it turns out if you have 24Gb fitted, and only 16Gb 'usable', some weird stuff happens with the network driver/stack, was stuck at <2mbps down for ages trying to figure it out, and only then discovered it by pure chance when I removed the 8Gb just cause it wasn't being used.
Anyway, short wait for iRacing to download (upto 14.5Gb now, pretty impressive) and then the usual fiddling to get it setup. DX11 is working pretty seamlessly for me, had to disable video capture but that's it.
Crossfire is working (at least in terms of not detrimental, no idea on framerates as not played around enough), settings are currently higher than previously and without my CPU overclock I think and framerates are ok, will drop the settings a bit but even when it dips <60fps it's still pretty smooth, better than it was it seems.
Anyway, also got to try the FR, I like it a lot more than I thought I would, the star mazda and me never got along, but this is good so far. Only did a handful of laps around Nurburgring GP, only did a 1:58 but can see 57 just with a clean lap and a 56 would be doable, this on the baseline setup with a car I don't know (usually takes a while) around a track I don't know that well.
Gonna try the AMG and a few other cars/tracks tomorrow before I decide but planning to put a bit more effort into it and getting a full season in for the first time in forever it seems like
