I have a friend who plays Minecraft on his Ivy Bridge integrated graphics (HD4000, built into a 3770). He's had perfectly acceptable performance on it until the Meltdown/Spectre patches were applied, at which point it turned into a stuttering mess. He rolled back the patch, and performance went back to acceptable.
Has anyone seen any benchmarks of the impact of the patches on IGPs? Have they been clobbered especially hard by these patches? I wouldn't have expected the minor CPU hit in gaming performance to really make that much of a difference (unless there's something to do with the weird way Minecraft is coded).