NVIDIA GeForce 840A vs NVIDIA GeForce GT 640 OEM Rebrand
Graphics Processor
| GPU model | GM108 | GF116 |
|---|---|---|
| Architecture | Maxwell | Fermi 2.0 |
| Foundry | TSMC | TSMC |
| Manufacturing process | 28 nm | 40 nm |
| Number of transistors | unknown | 1,170 million |
| Die size | unknown | 238 mm² |
| GPU variant | — | GF116-150-A1 |
Mobile graphics
| Release date | Mar 17th, 2014 | — |
|---|---|---|
| Generation | GeForce 800A | — |
| Production | End-of-life | — |
| Interface | PCIe 3.0 x8 | — |
| Predecessor | GeForce 700A | — |
| Successor | GeForce 900A | — |
Clocks
| Base clock | 1029 MHz | — |
|---|---|---|
| Boost clock | 1124 MHz | — |
| Memory clock | 1001 MHz 2 Gbps effective | 800 MHz 1600 Mbps effective |
| GPU clock | — | 720 MHz |
| Shader clock | — | 1440 MHz |
Memory Configuration
| Memory size | 2 GB | 1536 MB |
|---|---|---|
| Memory type | DDR3 | DDR3 |
| Memory bus width | 64 bit | 192 bit |
| Bandwidth | 16.02 GB/s | 38.40 GB/s |
Render Configuration
| Shading units | 384 | 144 |
|---|---|---|
| TMUs | 16 | 24 |
| ROPs | 8 | 24 |
| SMM count | 3 | — |
| Cache L1 | 64 KB (per SMM) | 64 KB (per SM) |
| Cache L2 | 1024 KB | 384 KB |
| SM count | — | 3 |
Performance
| Pixel rate | 8.992 GPixel/s | 4.320 GPixel/s |
|---|---|---|
| Texture rate | 17.98 GTexel/s | 17.28 GTexel/s |
| FP32 (float) performance | 863.2 GFLOPS | 414.7 GFLOPS |
| FP64 (double) performance | 26.98 GFLOPS (1:32) | 34.56 GFLOPS (1:12) |
Dimensions & Outputs
| Slot width | IGP | Single-slot |
|---|---|---|
| TDP | 33 W | 75 W |
| Outputs | No outputs | 2x DVI1x mini-HDMI |
| Length | — | 145 mm 5.7 inches |
| Suggested PSU | — | 250 W |
| Power connectors | — | None |
| Board number | — | P1062 |
API Support & Features
| DirectX | 12 (11_0) | 12 (11_0) |
|---|---|---|
| OpenGL | 4.6 | 4.6 |
| OpenCL | 3.0 | 1.1 |
| Vulkan | 1.1 | — |
| CUDA | 5.0 | 2.1 |
| Shader model | 5.1 | 5.1 |
Other Features
Graphics Card
| Release date | — | Apr 24th, 2012 |
|---|---|---|
| Generation | — | GeForce 600 |
| Production | — | End-of-life |
| Interface | — | PCIe 2.0 x16 |
| Predecessor | — | GeForce 500 |
| Successor | — | GeForce 700 |
