A New Framework

Classification of Rack Densities

Rack Density quantifies how much power an IT Equipment Rack can consume. Each category in our framework doubles from one to the next, borrowed from the telecommunications radio spectrum.

What are Rack Densities?

Rack Density is a measure or metric that quantifies how much power an IT Equipment Rack (also applicable to Telco Racks) can consume. It might refer to:

  • Average Rack Density: Average of Rack Power Consumption of a group of racks.

  • Design Rack Density: Maximum (peak) power at which an IT Rack is designed.

Rack Density correlates directly to hardware applications — servers, networking, storage, and determines the capacity of electrical components, distribution systems, and thermal systems at the facility level.

Each Density Category translates to a typical hardware profile and a suitable cooling technology. Conventional IT loads remain at or below 40 kW per rack; HPC and AI loads typically exceed 40 kW per rack.

Rack Density Categories

Seven categories — from LD to EHD

VHD (20–40 kW) is a bridge category that can support both conventional IT loads and some AI loads.

ABBR. RACK DENSITY CATEGORY RANGE
LD Low Density › 0 kW – 5 kW
MD Medium Density › 5 kW – 10 kW
HD High Density › 10 kW – 20 kW
VHD Very High Density › 20 kW – 40 kW
UHD Ultra High Density › 40 kW – 80 kW
SHD Super High Density › 80 kW – 160 kW
EHD Extremely High Density › 160 kW – 320 kW
CONVENTIONAL IT LOADS

Up to 40 kW / Rack

HPC & AI LOADS

Greater than 40 kW / Rack

Cooling Technologies and Rack Densities

Rack Densities and Cooling Technologies. comparing different air cooling and liquid cooling systems for data center racks, organized by rack density categories from low to very high, including various models and their power capacities in kilowatts.

HPC vs AI Systems Rack Densities Trend

Graph showing progression of high-performance computing systems from 1990 to 2030. Past systems like ASCI Red and BlueGene/L are marked, along with recent AI systems from Nvidia. The legend indicates supercomputers in black and AI systems in blue.

Understanding Rack Densities with their corresponding most useful cooling technology.

Rack Densities help in identifying and correlating:

  • IT Equipment power pattern

  • IT Equipment types/Performance

  • Cooling Technologies

Comparing Supercomputers with AI Systems, gives a sense of where we are today in terms of relative power consumption. AI Systems, should surpass Supercomputers in terms of Rack Density, possibly in this very decade, because of the market development pressure.

Understanding Extreme Rack Densities

Credits: Oak Ridge National Laboratory

Extremely High Rack Densities

Extremely High Rack Densities are related to potential future HPC and AI Loads

Comprises of four additional Rack Density categories related to the EHD (Extremely High Density) category (EHD: >160kW to 320kW)

Very EHD

2xEHD

>320kW to 640kW

500 kilowatt Category

VEHD

Ultra EHD

4xEHD

>640kW to 1280kW

1 Megawatt Category

UEHD

Super EHD

8xEHD

>1280kW to 2560kW

2 Megawatt Category

SEHD

Extremely EHD

16xEHD

>2560kW to 5120kW

3-5 Megawatt Category

EEHD

EHD

>160kW to 320kW

How New Rack Density Categories help Comparing Scenarios

A timeline chart showing the evolution of photovoltaic solar panel efficiency and power capacity over time, with labels for different High-Density categories and power ratings from 15kW to 5.1MW, highlighting past, current, and future AI system developments.

Our New training dedicated on how to support AI Systems (Hardware) in the Data Center is here, please take a look at:

https://www.seresdc.com/ai-data-center-training

A Glimpse into the future.

We created this Rack Density framework to better understand, and being able to compare different systems and technologies related to IT power density.

We are very close to enter into the arena of EHD (Extremely High Density) Rack Density, according to our framework it starts at 160kW/Rack.