NVIDIA Maxwell GPU Surface Book vs Intel Iris Graphics 6100 vs NVIDIA GeForce 930M

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 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.

NVIDIA GeForce 930M

The NVIDIA GeForce 930M (sometimes also called Nvidia GeForce GT 930M) is a (lower) mid-range, DirectX 11-compatible graphics card for laptops unveiled in March 2015. It is based on the last years GeForce 840M. In addition to the "normal" 25 Watt 930M, there is also a low power variant with a TDP of 12 Watt and support for DDR3 and GDDR5. The DDR3 variant should be approximately 10% slower than the 25 Watt version. The performance of the GDDR5 version is still unknown. The shader count for these low power 930M are also unknown. As the LP version is clocked only at 457 MHz + Boost it may feature more shaders (or a high Boost).

Update: The N16S-LP variant (5-12 Watt TDP, Low Power version?) will be available with GDDR5 starting in the first quarter of 2016. Later in 2016, the successor named GeForce 930MX was released that was available with GDDR5.

Architecture

Compared to Kepler, Maxwell has been optimized in several details to increase power efficiency. Smaller Streaming Multiprocessors (SMM) with only 128 ALUs (Kepler: 192) and an optimized scheduler should lead to better utilization of the shaders. Nvidia promises that a Maxwell SMM with 128 ALUs can offer 90 percent of the performance of a Kepler SMX with 192 ALUs. The 930M should feature the full GM108 with 3 SMMs (384 shader cores, 24 TMUs, and 8 ROPs due to the 64-bit interface). 

Another optimization is the massively enlarged L2 cache. The larger size can process some of the memory traffic to allow for a relatively narrow memory interface without significantly reducing performance.

Similar to GM107, the GM108 supports DirectX 12 with Feature Level 11_0 only.

Performance

The performance should be a bit below an average GeForce 840M due to the slower core clock. This means that demanding games like Evolve are only playable in lowest settings. Less demanding games like F1 2014 or Fifa 15 on the other hand should run in highest settings. See gaming benchmarks below for more details.

Features

GM108 integrates the sixth generation of the PureVideo HD video engine (VP6), offering a better decoding performance for H.264 and MPEG-2 videos. Of course, VP6 supports all features of previous generations (4K support, PIP, video encoding via NVENC API). Unfortunately, HDMI 2.0 is still not supported.

Power Consumption

The power consumption of the GeForce 930M should be about 33 Watts or less. Therefore, the 930M is best suited for laptops 13 inches in size or larger. The 900M series also supports Optimus to automatically switch between an integrated graphics card and the Nvidia GPU.