NVIDIA GeForce 840M vs AMD Radeon RX 6800S vs AMD Radeon RX 6700M

NVIDIA GeForce 840M

The NVIDIA GeForce 840M is a mid-range DirectX 12-compatible graphics card for laptops unveiled in March 2014. It is one of the first cards based on Nvidia's new Maxwell architecture (GM108 chip), but is still manufactured in 28 nm. The 840M offers 384 shader units clocked at 1029 MHz (+ Boost) as well as 2 GB of DDR3 memory (64 bit, 2000 MHz effective).

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. GM108 features 3 SMMs and thus 384 shader cores, 24 TMUs and 8 ROPs (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 Fermi and Kepler, the GM107/GM108 support DirectX 12 with feature level 11_0 only.

Performance

According to our benchmarks, the GeForce 840M is about 30 percent faster than the old GT 740M and just slightly behind a GeForce GT 750M (DDR3 version). Many games of 2013/2014 can be played fluently in WXGA resolution (1366 x 768) and medium or high detail settings. However, very demanding games such as Crysis 3 or Battlefield 4 will require lower resolutions and/or 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 840M should be about 30 Watts or lower. Therefore, the GPU is best suited for laptops 13 - 14 inches in size and above. The 800M series also supports Optimus to automatically switch between an integrated graphics card and the Nvidia GPU.

AMD Radeon RX 6800S

The AMD Radeon RX 6800S is a mobile high-end graphics card for gaming laptops. It uses the Navi 23 chip based on the new RDNA 2 architecture. It uses all 2,048 shaders (= 32 CUs), 128 TMUs, and 64 ROPs and therefore is similar to the desktop Radeon RX 6700 XT. The 128 Bit memory system connects 8 GB GDDR6 with 2 GHz memory clock. Furthermore, the RX6800S includes 32 MB Infinity Cache. The RX 6800S is the power saving variant of the RX 6800M and features slower clock speeds and a lower TDP.

Due to the lower clock speed, the performance should be lower than the RX 6800M. AMD specified the performance between the low power variants of the RTX 3070 (80-100W) and RTX 3080 (80-100W, former Max-Q).

The Navi 22 chip is manufactured at TSMC in the modern 7nm process. Thanks to the reduced TDP, the 6800S is suited for thin gaming laptops.

AMD Radeon RX 6700M

The AMD Radeon RX 6700M is a mobile high-end graphics card for gaming laptops. It uses the Navi 22 chip based on the new RDNA 2 architecture. It uses 2,304 of the 2,560 shaders (= 36 CUs), 144? TMUs, and 64 ROPs. The 160 Bit memory system connects 10 GB GDDR6 with 2 GHz memory clock. Furthermore, the RX6800M includes 80 MB Infinity Cache. AMD specified 2.3 GHz game clock for 10.6 TFLOPS theoretical FP32 performance at a TDP of 135 Watt. This means the GPU is in theory 11% slower than the RX 6800M.

The gaming performance of the RX 6700M is positioned slightly below a RTX 3070. When Raytracing effects are activated, it falls behind the GeForce GPUs.

The Navi 22 chip is manufactured at TSMC in the modern 7nm process.