The top of the range Intel graphics processors (Integrated: Iris Pro Graphics 6200) benchmarks to roughly the equivalent of:
NVidia: 9800 GX2, 285, 460 256-bit, 465
AMD : HD 6850, 7770, R7 260, R7 360
The more common Intel graphics processors in new builds (Integrated: HD Graphics 530) benchmark to roughly the equivalent of:
NVidia: 8800 Ultra, 9800 GTX, 9800 GTX+, GTS 250, GTS 450
AMD : HD 3870 X2, 4850, 5750, 6750, 7750 (DDR3), R7 250 (DDR3)
As said above, integrated graphics cards do not have dedicated memory for graphics, they share up to the value specified from the system actual physical memory, do if you have 8GB of memory in your machine, the integrated graphics card will use 1GB of that leaving you with 7GB for whatever you are running.
i5, NV960 2GB, 16GB memory, 2x 2TB Hybrid, Win10.
i3 , Intel integrated graphics, 6GB memory, 512GB Generic SATAIII Win8.1.
Intel Celeron (duel Core), Radeon integrated graphics, 4GB memory, 180gB Generic SATAII, WinVista.
Q6600, Intel integrated graphics, 8GB memory, 512GB Generic SATAII, Win7.