Multiple BSODs (atikpmag.sys while idling, stop 0x00000000124 in BF3)

Hey all.

My first time here posting, I've used other peoples threads many a time to solve other issues so I already owe a thanks here! Here's my situation.

About 6 months ago my system started messing up big time, I was getting an error where my displays would simply shut off, the system would continue powered on but unresponsive (no change to numlock) and all I could do was restart. There was no errors anywhere, no sign anything had gone wrong, nothing. Eventlog didn't mention anything going wrong before it noted the system had powered up from an unexpected shutdown. With very little to go on, no results online turning up anything useful, and seeing as I'd been looking to upgrade a number of components in my system anyway, I went ahead and rebuilt my machine. I bought a new GFX card, all new memory, new disk drives and a new PSU. I brought my motherboard, CPU and HDD's over as I'd recently upgraded those anyway. The problem seemed to go away. I don't know if this is related, but I thought I'd mention it anyway.

Now, recently I've started getting BSODs. As I've said in the title, it's one of two - either an atikpmag.sys error, which I'll get just while my system is idling (just web browsing or something like that). Or it's a stop error 0x000000124 (probably got the wrong number of 0's there) and I've only had this when it's under load (playing Battlefield 3). Must of the components in the system are new as explained above, and it's been running smoothly for the last 6 months. Before that it'd been running fine for a little under a year before I got the previous error. I'm fairly confident with tech, and can normally self-diagnose, but I'm at an end here. I've disabled all kinds of overclocking, I've turned off all the fancy power-saving features for my mobo through bios and I've updated drivers. Other the last 4 days particularly it's started to increase and I'm now getting daily, sometime twice daily, BSODs. The system appears to be functioning totally fine all the rest of the time, and the errors don't seem to be chaining so I don't think it's an overheating issue.

When I get the atikpmag.sys error, my two screens will switch off, then one by one switch back on and off again for about 10 seconds, sometimes turning on to black, sometime back to the desktop, before it finally goes to the BSOD. It's almost identical every time.

I've run the SF Diagnostic tool and attached it here, the Minidumps go back quite a way, I've renamed them to better reflect which error I got each time (I did this as it happened), which should make it more useful. Also a quick thing to note, the diagnostic tool will say I'm running the 12.9 BETA Catalyst drivers. I've literally only updated to those in the last 30 minutes and all the BSODs were under the 12.8 STABLE drivers, I'm yet to experience one under 12.9 (but it's hardly been very long yet!).

All help would be appreciated, thank you in advance.