Getting the TITAN RTX’s and NVLink Bridge Setup
Setting up our GPUs is simple. We insert our NVIDIA Titan RTX cards in the appropriate PCIe slots and connect the bridge. We will be using Windows 10 Pro for many of our tests. Once we booted to the desktop we download the latest drivers and install them, at the time of writing the driver version is 419.67. We right-click on the desktop and select the NVIDIA Control Panel.
If SLI is not enabled, you can do that here. Years later, we are still enabling SLI for our two $2500 desktop GPUs. As much as things change, they sometimes stay the same.
Confirming everything is in order, we check system information.
So far everything is looking good. Since we have this setup using Windows, we can validate that it is working using NVLinkTest.
Here this text output for NVIDIA’s p2pBandwidthLatencyTest:
You will notice that this is similar to the Linux p2pbandwidthtest output we saw in Gigabyte G481-S80 8x NVIDIA Tesla GPU Server Review the DGX1.5 and Inspur Systems NF5468M5 Review 4U 8x NVIDIA Tesla V100 GPU Server.
We will use the same software that we have used on all our reviews while on Windows 10 Pro.
Software Used: ASUS GPU Tweak
GPU Tweak II software from ASUS used to set different configs and monitor GPU data for its graphics cards. Although the graphics are relatively large when displayed onscreen, it can be minimized to the taskbar when not needed.
GPU Tweak II was also used on our Titan RTX review; we used the same settings here.
ASUS GPU Tweak sees both Titan RTX’s and applies the different modes to each GPU. You can see the different GPU’s in the graphs where one is colored Red, and the other is colored Blue. The Red part of the graphs is the primary GPU, and we will note that both GPU’s do not show identical numbers. An example for that is while sitting on the desktop GPU #1 (Red) or the primary GPU is doing most of the work while GPU #2 (Blue) idles. We can also see this effect while benchmarks are running GPU #1 (Red) or the primary GPU is doing most of the work while GPU #2 (Blue) ramps up when needed, loads appear to balance back and forth between the GPU’s.
Next, let us take a look at the NVIDIA Titan RTX NVLink specifications and our test setup then continue on with our performance testing.
NVIDIA Titan RTX Key Specifications
Here are the key specifications for the NVIDIA Titan RTX:
- Graphics Processing Clusters: 6
- Texture Processing Clusters: 36
- Streaming Multiprocessors: 72
- CUDA Cores (single precision): 4608
- Tensor Cores: 576
- RT Cores: 72
- Base Clock (MHz): 1350 MHz
- Boost Clock (MHz): 1770 MHz
- Memory Clock: 7000 MHz
- Memory Data Rate: 14 Gbps
- L2 Cache Size: 6144 K
- Total Video Memory: 24GB GDDR6
- Memory Interface: 384-bit
- Total Memory Bandwidth: 672 GB/s
- Texture Rate (Bilinear): 510 GigaTexels/sec
- Fabrication Process: 12nm FFN
- Transistor Count: 18.6 Billion
- Connectors: 3x DisplayPort , 1x HDMI, 1x USB Type-C
- Form Factor: Dual Slot
- Power Connectors: Two 8-Pin
- Thermal Design Power (TDP): 280watts
- Thermal Threshold: 89C
- NVLink: 100GB/s
One will notice that on the previous page we achieved over 93GB/s for our NVLink which is in the ballpark of the 100GB/s quoted in the specs. Combined, the two GPUs have massive compute resources as well as 24GB of memory per card. This is important since we effectively have two cards with P2P enabled and a total of 48GB of memory. This is much more than we would see with older generation desktop parts.
Testing the NVIDIA Titan RTX with NVLink
Here is our test setup for the dual NVIDIA Titan RTX:
- Motherboard: ASUS WS C621E SAGE Motherboard
- CPU: 2x Intel Xeon Gold 6134 (8 core / 16 Threads)
- GPU: 2x Titan RTX’s with NVLink
- Cooling: Noctua NH-U14S DX-3647 LGA3647
- RAM: 12x MICRON 16GB Low Profile
- SSD: Samsung PM961 1TB
- OS: Windows 10 Pro
- PSU: Thermaltake Toughpower DPS G RGB 1500W Titanium
The PCIe layout of the ASUS WS C621E SAGE Motherboard allows for us to use the 4-Slot Bridge with the first Titan RTX in slot #3 and the second Titan RTX in slot #7, this leaves two slots open for air-flow. We would use slot #1 or #2 for a 10GbE network card.
We can see a similar motherboard and setup being used in the bespoke systems that we suspect will house many dual NVIDIA Titan RTX with NVLink systems for the deep learning and creative communities.
Let us move on and start our testing with computing-related benchmarks.