Let’s say you’re considering buying an open-frame server rack to house your data center equipment. You like that the open design offers great ventilation for hot server equipment and that the racks hold a lot gear, are a cinch to assemble and cost less than enclosed cabinets.

But you still have a decision to make: Do you go with a two-post rack or a four-post rack? This blog posting will help you find the answer. We start by describing the basic design features of the two and their best uses. Then we contrast some of their main differences: capacity, footprint, mobility, cost, assembly and cable management features.

Design Feature Differences

A four-post open-frame rack is like the skeleton of a cabinet, so it takes up the same floor space but is lighter and easier to access. With its back rails it can support deeper, heavier server equipment that two-post racks cannot. All NavePoint’s models are made of cold-rolled steel and can be either floor-mounted or placed on caster wheels.

We offer two basic designs of two-post open-frame racks. The racks shaped like an upside-down T have large capacities, up to 45U, and are placed either on the floor or on caster wheels. The L-shaped desk racks are shorter, up to 12U. Both designs are made of a rugged, cold-rolled steel, and a few models come in a lighter-weight aluminum.

4-Post Rack Best Uses

Floor-mounted four-post open-frame server racks hold equipment that is heavier and/or has extended depth, such as servers, routers, monitors, deep rack shelves and uninterruptible power supplies that require rear support. Other benefits of four posts compared to two posts:

• Greater capacity
• More attachment points for cable management accessories
• More expandable for future equipment additions
• A box-like perimeter that protects from accidental bumps

2-Post Rack Best Uses

Two-post open-frame server racks hold lighter equipment that doesn’t need rear support, such as patch panels, switches and most rack-mount drawers. Other benefits compared to four-post racks:

• Smaller footprint, especially for computer closets and on desks and cabinets
• Lower cost
• Easier to move
• Easier to assemble
• Slightly easier to access equipment

Server Rack Capacity

Four-post server racks can hold more equipment and more weight. At NavePoint you can choose from eight rack sizes, from 9U to 45U. All of them have adjustable depths – some from 2.5 to 22.6 inches in 1.5-inch increments, and others from 22 to 40 inches. You will never worry about load capacity, as the vast majority hold at least 800 pounds and half hold at least 1,300 pounds.

Our two-post server racks are offered in seven vertical sizes, from 6U to 45U. The desk racks can hold 330 pounds, or 660 pounds for the heavy-duty models. Most of our taller two-post racks hold either 660 or 880 pounds.

Server Rack Footprint

A two-post rack can take up significantly less floor space, depth wise. Our four-post models have a range of depths from 20 to 40 inches. Our two-post desk racks require a minimum depth of only 12 inches. With their vertical capacity options of 6U to 12U, you can use them to make a room more space efficient without crowding the floor.

Server Rack Mobility

Though most four-post server racks can be deployed either with or without caster wheels, because of their larger size they are generally less mobile than two-post racks. NavePoint’s two-post desk racks have four rubber feet and are heavy enough to be stable on a desk or cabinet but light enough to move if needed. Two-post floor racks can be anchored to the floor or placed on casters, though having one on wheels will lower its weight capacity.

Server Rack Cost

Two-post server racks cost about one-third less than four-post racks. However, there is a bigger price difference among NavePoint’s desktop racks, where the regular-duty models cost about half as much as the heavy-duty ones.

Server Rack Assembly

Both types of open-frame racks are easy to assemble. A two-post rack comes in only four to six pieces. The largest four-post rack is about 20 pieces, but can still be assembled with a screwdriver and a wrench.

Server Rack Cable Management

Compared to two-post racks, racks with four-posts have twice as many attachment points for cable management accessories such as raceways, cross bars, D-rings and patch panels. This is a big consideration if you expect to have bunches of cables plugged into the rear of the rack.

Our two-post and four-post open-frame racks are in-stock and available with FREE standard same-day shipping. If you have product questions or need recommendations, contact our U.S.-based team of experts at 1-866-392-1613 or email us.