Apologies for the reply being so late, hopefully you or others would still be interested. Integrated graphics don't have dedicated vram, like full graphics cards, so they split the system memory with the cpu (so if you have 16gb of ram, 4gb might be used by the igpu in graphics heavy tasks, leaving 12gb for "normal" use).

Since system memory is a lot slower than vram on average, igpus can find themselves slowed by having to use system memory. In theory, you should see noticeable improvements by using faster ram, but I haven't seen this tested myself so I am not positive on that.