Pros

Performance on the 5GHz band is potentially very good; can be used with notebooks, unlike larger USB adapters

Cons

Performance on the 2.4GHz band is no better than an adapter at half the price; best 5GHz performance only achieved using an optional USB extension cable, allowing the adapter to be pointed towards the router; very bulky for use plugged into a USB port

Star Rating

Rosewill N900UBE

Introduction

The Rosewill N900UBE Dual-Band Wireless N USB Adapter is a large USB form factor wireless adapter with a flip-out antenna. It measures 3.43" x 1.05" x 0.71", which pushes the limits of what a device designed to be plugged directly into a USB port should be, as it blocks any directly adjacent ports, and sticks out a significant amount from the side of a notebook or back of a desktop. 

Features

The main features of the N900UBE are its dual-band operation, 450mbps upload and download rating, and its USB form factor. There are very few adapters on the market that can offer these features. The N900UBE is packaged with a manual and a CD-ROM containing the drivers, but no accessories.

In Use

Performance

Performance was all over the map, for one simple reason: this adapter is completely unidirectional.

On the 2.4GHz band, it performed only slightly better than a typical inexpensive single-band adapter or a notebook's built-in wireless. It achieved between 20mbps and 32mbps on two test systems, with the best result of 32mbps (4MB/s) right next to the router. The problem is definitely the unidirectional nature of the adapter. For instance, on a notebook test system, transfer speed increased from 24mbps to 31mbps simply by turning the notebook in order to point the N900UBE's antenna straight out in the direction of the wireless router several rooms away. This is impractical for regular use, and impossible on a desktop. 

The situation was similar on the 5GHz band, although speeds were much higher. Plugged into a rear USB port of a desktop test system tucked into a corner, the transfer rate was a disappointing 40mbps (5MB/s). But when the N900UBE was plugged into a USB extension cable, which was not included with the adapter, and the antenna was pointed directly at the router several rooms away, the N900UBE achieved sustained transfer speeds of between 84mbps and 120mbps (12-15MB/s).

Conclusion

We've emphasized this in other networking product reviews, and we'll say it again here. Performance on the 2.4GHz band peaked long ago, and can be achieved with very inexpensive products. The N900UBE offered absolutely nothing over adapters that cost half as much when used on this band.

The performance on the 5GHz band, on the other hand, was more interesting. Because of the unidirectional nature of the N900UBE's antenna, for the most part, the N900UBE was inferior to stand-alone USB adapters (like the N600UBE reviewed here), because it cannot be easily positioned. But when used with an optional USB extension cord and pointed in the direction of the wireless signal, the N900UBE absolutely took off, connecting at its rated 450mbps, and providing actual sustained throughput of 120mbps (15MB/s). That is actually nearly 50% faster than the N600UBE, which is only rated at 300mbps.

So, how do we rate this product? We're torn, because the N900UBE packs a lot of capability into its relatively compact design. But at the same time, it's clearly pushing the limits of what a small adapter like this can do. If Rosewill had included an extension cord so that it could at least optionally be positioned appropriately for desktop use, we'd rate it higher, but as shipped, we give it 3.5 out of 5 stars.

The Rosewill N900UBE Dual-Band Wireless N USB Adapter is currently available for $39.99 shipped from Newegg.

Special thanks to Rosewill and Newegg for providing this review sample.