Graphics Core Performance
The energy-efficient processors are slower than their full-featured cousins at computing loads due to reduced clock rates. The aggressive Turbo Boost settings cannot make up for the difference in their frequencies.
The speed of the integrated graphics core is yet another aspect of performance, though. Obviously, energy-efficient processors are likely to be used in configurations that lack a discrete graphics card, so it is important for the S and T series models to have a fast integrated core. That's where they are going to show their strong side because they are equipped with the full-featured HD Graphics 4600 clocked at the same frequency as in the regular desktop Haswell-based products. In other words, the energy-efficient processors are going to be alike in their graphics performance to the regular models. Let's check this out.
As a tentative test of the 3D performance of the integrated graphics cores, we will run Futuremark 3DMark. Its Sky Driver test is designed to benchmark 3D performance of typical midrange home PCs whereas the most resource-consuming Fire Strike test is targeted at advanced gaming configurations.
Each of the tested processors is equipped with a GT2-class graphics core with 20 execution devices but we should keep it in mind that the clock rate of this core varies slightly between the particular processor models. The HD Graphics 4600 core in the i5-4670, i5-4670S and i5-4670T is clocked at up to 1.2 GHz. In the i5-4590 and i3-4360 its clock rate is 1.15 GHz and in the i5-4460, it's 1.1 GHz. Considering this fact, it becomes clear that the 3D performance results depend on the graphics core, which is the same in the energy-efficient models as in the 84-watt ones. Moreover, the Core i5-4670S and Core i5-4670T find themselves in between the Core i5-4670 and Core i5-4590, unlike in the computing tests above.
Anyway, 3DMark is a synthetic benchmark, so it wouldn't be quite correct to form any general conclusions on its basis. Let’s first check out the integrated graphics cores in actual 3D games. We will run our tests at the Full-HD resolution (1920x1080 pixels) with low visual quality settings. We do not enable full-screen antialiasing.
The average frame rate in games is somewhat affected by the processor’s computing performance but the graphics core is, of course, the most crucial factor. Therefore the Core i5-4670S and Core i5-4670T deliver good performance, being somewhere in between the Core i5-4670 and Core i5-4590. The only exception is the rather CPU-dependent MMO World of Tanks, yet even in this game the energy-efficient Core i5-4670S is quite comparable to the 84-watt processors in performance. The Core i5-4670T falls behind because its top clock rate is lower than that of the full-featured Haswell CPUs even with Turbo Boost enabled. The difference of just a few frames per second can hardly matter for all practical purposes, though.
Thus, we can see no difference between the 84-watt and the energy-efficient processors in gaming applications.