Though the same memory serves on-die graphics, 3DMark 11 actually suggests that CPU-heavy tasks gain most from increased DRAM data rates.
I began 3DMark Professional Edition testing with the app's low-end Ice Storm test, only to have a "what the...?" moment after switching over to integrated graphics. Looking for performance differences attributable to memory, I was stunned to see just how badly Intel gimped the GPU on its LGA 1150-based processor compared to the embedded version. We told Intel this before Haswell launched, but I believe the company underestimated the market for a socketed processor with Iris Pro graphics 5200.
Cloud Gate pulls the Core i7-4770K's HD Graphics 4600 into the low 20s, while the embedded CPU's Iris Pro graphics 5200 engine cruises through unscathed. Again we see only minor performance differences attributable to memory data rate.