NVIDIA Maxwell GPU Surface Book vs Intel Iris Graphics 5100 vs Intel Iris Graphics 6100

NVIDIA Maxwell GPU Surface Book

The Nvidia Maxwell GPU is a dedicated graphics card in the Microsoft Surface Book laptop. It is based on the Maxwell GM108 chip as the Geforce 940M with 384 shaders. Instead of the DDR3 graphics memory, the Surface Book graphics card features faster GDDR5 memory (both 64 Bit though). 

Thanks to the faster graphics memory, the Surface Book Geforce is performing better than the average GeForce 940M. However, the 945M and GTX 950M are still noticeably faster. Demanding games therefore only run in low settings fluently.

More details can be found in our extensive review of the 2015 Microsoft Surface Book with the dedicated Maxwell GPU.

Intel Iris Graphics 5100

The Intel Iris Graphics 5100 (GT3), also called HD Graphics 5100, is a processor graphics card included in some of the Haswell processors of 2013. It represents the highest configuration of the integrated graphics unit (40 execution units), but lacks the additional eDRAM cache of the Iris Pro Graphics 5200. The base clock can be automatically overclocked using Turbo Boost technology. Depending on the processor model, the base and turbo clock rates may differ, resulting in varying graphics performance between CPU models.

In comparison to the HD 4000, the graphics core has been modified extensively. The GPU supports DirectX 11.1, OpenCL 1.2 and OpenGL 4.0. It also features an improved decoder for 4K videos and the fast Quick Sync encoder.

The performance of the Iris Graphics 5100 is about 20 percent above the HD Graphics 5000, which can be found in ULV CPUs of the 15W class. In a best case scenario, the IGP machtes a dedicated GeForce GT 640M LE. In other cases, however, the performance is only at the level of the GeForce GT 620M due to the limited memory bandwidth. Current games (as of 2013) can be played fluently in low or medium detail settings and a resolution of 1.024 x 768 or 1.366 x 768 pixels.

Due to the 22nm 3D Tri-Gate production process, power consumption should be relatively low. The Iris Graphics 5100 can be found on certain ULV dual-core Haswell models in the 28 Watt TDP range.

Intel Iris Graphics 6100

The Intel Iris Graphics 6100 (GT3) is an integrated Broadwell graphics card revealed in Q1 2015. It can be found in several low-voltage SoCs (28 W TDP) such as the Core i5-5257U or i7-5557U. While Core i5 and Core i7 chips feature 48 EUs, the Core i3 version offers just 47 EUs. Depending on the specific CPU, the maximum GPU frequency varies between 1000 and 1100 MHz.

Architecture and Features

Broadwell features a GPU based on the Intel Gen8 architecture, which has been optimized in various aspects compared to the previous Gen7.5 (Haswell). Inter alia, the shader arrays called "subslice" have been reorganized and now offer 8 Execution Units (EUs) each. Three subslices form a "slice" for a total of 24 EUs. Combined with other improvements such as larger L1 caches and an optimized frontend, the integrated GPU has become faster and more efficient than its predecessor.

The Iris Graphics 6100 represents the top-end version of the Broadwell GPU family and consists of two slices with 48 EUs. Beyond that, there is also a low-end (GT1, 12 EUs), a mid-range (GT2, 24 EUs) and a high-end variant (GT3e, 48 EUs + eDRAM).

All Broadwell GPUs support OpenCL 2.0 and DirectX 12 (FL 11_1). The video engine can now decode H.265 using both fixed function hardware as well as available GPU shaders. Up to three displays can be connected via DP 1.2/eDP 1.3 (max. 3840 x 2160 @ 60 Hz) or HDMI 1.4a (max. 3840 x 2160 @ 24 Hz). HDMI 2.0, however, is not supported.

Performance

Depending on the specific CPU, the maximum GPU frequency varies between 1000 and 1100 MHz. Even though the Iris Graphics 6100 is technically identical to the HD Graphics 6000, the higher TDP (28 W instead of 15 W) leads to a better utilization of the Turbo Boost and therefore a superior performance. Overall, the Iris 6100 is about as fast as a dedicated GeForce 820M and outperforms the former Iris Graphics 5100 by 20 - 25 percent.

Older and less demanding games such as Diablo III, Counter-Strike: GO oder Dota 2 can be played fluently in 1366 x 768 pixels and high settings. More demanding titles, however, may require lower settings or won't run at a decent framerate at all.

Power Consumption

Utilizing a new 14 nm process, the Broadwell LV chips are specified at 28 W TDP and therefore suited for medium-sized ultrabooks. The TDP is flexible and can be further reduced (23 W), which has a significant impact on performance.