Now before anyone says that my GPU is the issue (usually it would be) when I was running Windows 7 with my GPU drivers all up to date I was able to run BF3 on low settings at 1024x768 (auto graphics settings says I can run it a bit higher though) with not much lag (in fact it ran better than the youtube video I saw that proved that BF3 can run on an Intel HD 3000) but now as I'm using Windows 8 also with my drivers up to date BF3 lags from the get go and some in the Battlefield forums seem to hint that it might be a Windows 8 problem. Has anyone experienced this issue and if it is an issue with Windows 8 is there an update or fix for the lag? BF3 along with Borderlands 2 and Tomb Raider are the only games that I currently own that show performance problems on my Windows 8 laptop (although Tomb Raider is more of a driver issue) and I don't want to go through the hassle of putting Windows 7 back on for 3 games (Installing Windows and uploading my games eats up so much of my time).
For me and plenty other gamers, BF3 is running with higher frame-rates and the whole game-play is much smoother under Windows-8, but I don't know any gamers which are running BF3 without a proper dedicated GPU or even SLI.
You're managing to run that game on a laptop on-board graphics? Wow... I didn't know that would be possible, or reasonable. Apologies but this is "new" for me and I can't help really.
I suggest, you try to reduce the resolution (if possible) by one more tier to see if there are performance improvements.