It doesn't like the 4GB memory sticks I had in the Biostar board so I'm currently running it with some donor 1GB sticks = 4GB total memory. I might be able to fix this later but the Asrock memory stick compatibility list seems to only like 4GB sticks that are double-sided and these sticks are single-sided i.e. they have fewer chip packages than the qualified memory on the website list so the SS sticks may have higher bus loads that the Asrock memory interface can't handle.
The video took some tweaking to get working but it's all right now -- apparently if the default sound-over-HDMI setting is left enabled in the BIOS that kills the DVI dual-link option which I need for the onboard Radeon graphics to run my main monitor at 2560x1440. This mobo has three PCI-e slots for heavy-duty video card Crossfire, at the moment I'm using none of them. Maybe later, but running multiple video cards is a gamer thing and I'm not much into games.
The audio drivers needed updating, a simple download and install made the sound system work as much as I need it for the headphones I typically use -- the mobo supports digital audio, surround sound etc. which my tin ear wouldn't appreciate.
My old-school PS/2 cable splitter doesn't work on this mobo unlike the Biostar board it replaced. I'm using the single PS/2 connection for my keyboard and a spares-box USB mouse rather than the fit-my-hand PS/2 mouse I've used for ages. I'll fiddle with this a bit more later, USB-PS/2 adaptors are cheap but sometimes they don't work.
The real miracle is that my original boot disk with its Windows 8 image configured for the Biostar board just worked on this new mobo. Great shock, I didn't expect that. Windows, it Just Works.
One annoyance is that I've lost the useful Centronics LPT port on the Biostar board which was accessible via a header and a cheap ribbon cable from Amazon. This Asrock board doesn't have a similar LPT port which means I'm going to have to fiddle a bit to get my old-school laser printer to work; there's a USB-Centronics adapter in a box somewhere behind me I'll experiment with later.
Next thing to try is flashing the BIOS to the most up-to-date version, that might fix the problems with the 4GB memory sticks. Maybe. The new BIOS enables the board to use Piledriver and Bulldozer chips if I decide to upgrade in the future.
EDIT: powered the machine up this morning and Windows wanted to have a word with me. Since I had swapped out the motherboard the system reckoned this was a significant enough change to the hardware spec (no shit Sherlock) that it wanted me to reactivate the original Win8 licence. This required phoning an 0800 helpline and punching in a lot of numbers and then listening to another long list of numbers and typing them into the system. Luckily I didn't drop any of them and got it right first time so everything's good. I presume I've got a couple of similar activations in reserve before MS would stop revalidating this licence key. I don't really want to find out the hard way, thank you Jesus.