NVIDIA Tesla K40c vs NVIDIA Tesla K40m Comparison

Head-to-Head Benchmarks

The only direct comparison in the database is the Geekbench OpenCL test, where the NVIDIA Tesla K40m scores 19,885 and the NVIDIA Tesla K40c scores 17,468. The K40m wins outright by a 13.8% margin. This is not a narrow edge; it is a decisive gap in raw compute throughput that separates the two cards by more than a full tier in the benchmark hierarchy.

Looking at where each card sits relative to its closest competitors clarifies the meaning of that score. The K40m, with its average benchmark score of 19,885, lands at the 65th percentile among all GPUs. Its nearest rival is the AMD FirePro W7000 at 19,905, a difference of just 0.1%, which effectively places them in a statistical tie. The K40m also leads the AMD Radeon RX 6650 XT by 0.6% and the AMD FirePro D300 by 1.3%, with the NVIDIA Quadro K5200 trailing by 1.4%. These are small margins, but the K40m is consistently ahead of all four, showing that its OpenCL result is not an outlier but a stable position among comparable workstation and consumer parts.

The K40c, by contrast, scores 17,468 and sits at the 61st percentile. Its nearest rival is the AMD Radeon Pro 460 at 17,509, which is 0.2% ahead, meaning the K40c is actually slightly behind its closest competitor. The AMD Radeon Pro 560 leads it by 0.5%, the AMD Radeon 780M by 0.7%, and the NVIDIA GeForce RTX 4060 by 1%. The K40c is the underdog in every one of these matchups, and its 13.8% deficit against its sibling card is far larger than any of the differences in its own rival set. The data paints a clear picture: the K40m is the stronger performer, and the K40c sits in a lower performance band despite sharing most of its core architecture.

The win count reflects this. The K40m wins the single head-to-head benchmark, while the K40c wins none. There is no other test in the database to offset that result, so the K40m holds a clean 1-0 record. The delta of 13.8% is substantial enough that it would likely persist across other compute workloads, though the database only records this one metric.

The Verdict

The benchmark data is unambiguous: the NVIDIA Tesla K40m outperforms the NVIDIA Tesla K40c. The 13.8% advantage in Geekbench OpenCL is the only recorded comparison, and it favors the K40m. Anyone choosing between these two cards strictly on measured performance should select the K40m.

The K40m also holds a better position in the broader GPU landscape. Its 65th percentile rank versus the K40c's 61st percentile means the K40m is closer to the middle of the performance distribution, while the K40c slips further down. The K40m's nearest rivals are all within 1.4%, indicating it competes in a tight cluster of similarly scoring cards. The K40c's nearest rivals are also close, but they are all ahead of it, which is a less favorable position.

For tasks that rely on OpenCL compute, the K40m is the rational pick. The K40c is not a weak card in absolute terms, but it is measurably slower than its sibling, and the data shows no scenario where the K40c wins. The verdict is straightforward: choose the K40m for higher compute throughput, and only consider the K40c if external factors outside this benchmark data dictate otherwise.

Architecture Differences

Both cards are built on the Kepler architecture and use the TSMC 28 nm process node. The transistor count is identical at 7,080 million, and the die size is the same at 561 mm², yielding a transistor density of 12.6M per mm². The key difference lies in the chip designation: the K40m uses the GK110B, while the K40c uses the GK180. This is not a cosmetic distinction; the chip revision affects how the hardware behaves under load.

The GK110B in the K40m is a later revision of the GK110 family, and the GK180 in the K40c is a separate designation. Despite the different chip names, the core counts match exactly: 2,880 shading units, 240 texture mapping units, and 48 raster operation units. The architecture supports the same feature set for the most part, with both cards reporting OpenGL 4.6 and Vulkan 1.2.175. However, the DirectX support differs: the K40m lists DirectX 12 (11_1), while the K40c lists DirectX 12 (11_0). The 11_1 feature level includes additional shader capabilities and resource binding improvements that the 11_0 level lacks, which could matter in compute workloads that leverage those extensions.

The clock speeds are identical: a base clock of 745 MHz, a boost clock of 876 MHz, and a memory clock of 1502 MHz with 6 Gbps effective data rate. The pixel rate is 52.56 GPixel/s, the texture rate is 210.2 GTexel/s, and the FP32 throughput is 5.046 TFLOPS for both. The memory subsystem is also identical: 12 GB of GDDR5 on a 384-bit bus, delivering 288.4 GB/s of bandwidth. The fact that the K40m achieves a 13.8% higher OpenCL score despite identical specifications suggests either a more efficient implementation of the GK110B versus the GK180, or a difference in how the silicon is binned or configured that does not appear in the listed specs.

The power profile is the same: both have a TDP of 245 W and a suggested PSU of 550 W. The slot width is dual-slot, and the length is 267 mm (10.5 inches). The K40c lists power connectors as 1x 6-pin plus 1x 8-pin, while the K40m does not list its connectors in the database. This could indicate a physical difference in power delivery, but without connector data for the K40m, it is not possible to confirm whether the power input differs.

Specification Differences

The two cards share nearly every specification, which makes the performance gap even more striking. The only fields where they differ are the chip name, the DirectX version, the power connector listing, and the release date.

• Chip: K40m uses GK110B, K40c uses GK180
• DirectX: K40m supports 12 (11_1), K40c supports 12 (11_0)
• Power connectors: K40c lists 1x 6-pin + 1x 8-pin, K40m has no listed connectors
• Release date: K40m launched on 2013-11-21, K40c launched on 2013-10-07

The release date difference is notable: the K40c came out roughly six weeks earlier. The K40m is a later revision, which may explain why it scores higher despite identical specs. The DirectX feature level difference is the only hardware-level feature discrepancy that appears in the API support, and it could be a factor in the OpenCL score if the benchmark exercises DirectX-related compute paths.

Everything else matches: both have 12 GB GDDR5, 384-bit bus, 288.4 GB/s bandwidth, 2,880 shading units, 240 TMUs, 48 ROPs, 5.046 TFLOPS FP32, 245 W TDP, 550 W suggested PSU, PCIe 3.0 x16 interface, no display outputs, dual-slot width, 267 mm length, and end-of-life production status. The launch MSRP is identical at 7,699 USD for both. The predecessor is Tesla Fermi and the successor is Tesla Maxwell for both cards.

FAQ

Q: Which card has a higher Geekbench OpenCL score?

A: The NVIDIA Tesla K40m scores 19,885, while the NVIDIA Tesla K40c scores 17,468, giving the K40m a 13.8% lead.

Q: Are the two cards identical in specifications?

A: No. They share most specs including 12 GB GDDR5, 2,880 shading units, and a 245 W TDP, but the K40m uses the GK110B chip while the K40c uses the GK180 chip. The K40m also supports DirectX 12 (11_1) while the K40c supports DirectX 12 (11_0).

Q: How does the K40m compare to its nearest rivals?

A: The K40m is 0.1% behind the AMD FirePro W7000, and 0.6% ahead of the AMD Radeon RX 6650 XT, 1.3% ahead of the AMD FirePro D300, and 1.4% ahead of the NVIDIA Quadro K5200.

Q: How does the K40c compare to its nearest rivals?

A: The K40c is 0.2% behind the AMD Radeon Pro 460, 0.5% behind the AMD Radeon Pro 560, 0.7% behind the AMD Radeon 780M, and 1% behind the NVIDIA GeForce RTX 4060.

Q: What is the release date difference between the two cards?

A: The K40c launched on 2013-10-07, and the K40m launched on 2013-11-21, so the K40m came out about six weeks later.

Q: Do both cards have the same memory bandwidth?

A: Yes, both have 12 GB of GDDR5 on a 384-bit bus with 288.4 GB/s bandwidth and a 1502 MHz memory clock.

Where Each One Wins

The NVIDIA Tesla K40m wins in the only recorded benchmark, the Geekbench OpenCL test, with a 13.8% advantage over the K40c. This makes it the clear choice for any compute workload that relies on OpenCL performance. The K40m also holds a higher percentile rank at 65 versus the K40c's 61, indicating that it positions better against the broader GPU population.

The K40c does not win any benchmark in the database. Its scores fall behind all four of its nearest rivals, and it trails the K40m by a wide margin. The K40c's only potential advantage is its earlier release date, which might matter in scenarios where a specific firmware or driver version was required, but the database does not contain any performance data that supports a preference for the K40c.

The K40m is also the better choice for users who need the DirectX 11_1 feature level, as the K40c only supports 11_0. This could be relevant for certain compute or rendering applications that leverage the higher feature level. The K40m's later release date and revised chip (GK110B) suggest a more mature implementation, and the benchmark data confirms that the K40m extracts more performance from the same core configuration.

In practical terms, the K40m wins for OpenCL compute, for relative standing among rivals, and for API compatibility. The K40c is not competitive in any measured category. Users with workloads that depend on the specific power connector configuration might note the K40c lists 1x 6-pin plus 1x 8-pin, but since the K40m's connectors are not listed, this is not a point of comparison. Based on the recorded data, the K40m is the superior card in every measurable way.