Wireless Performance

By TG Publishing Team, published on October 18, 2003
Source: Tom's Guide US | Keywords: , ,
Contents

3. Wireless Performance

Although I have a USB2-equipped desktop machine, the notebook that I normally use for client testing remains at USB 1.1. But not to be kept from my appointed throughput-testing rounds, I just connected a Belkin F5D7130 AP [reviewed here] to my notebook and left the USB-G54 lashed to my 2.4 GHz Pentium4 desktop, sitting where the test AP normally is. Figure 2 shows the test results.

Figure 2: Four location throughput
(click on the image for a full-sized view)

I should note that you can't directly compare these results - or any results going forward - with those of previous reviews before October 1, 2003. My recent move meant setting up new test locations, which are described here.

The new Location 3 test is the only one done from a point one floor below the stationary AP location. The poorer performance for Location 3 might be due to the unusual antenna design of the USB-G54, but it could just be the way the radio waves crumble in the new test location. Only time - and more product testing - will tell for sure.

I also ran tests in WEP128, WPA-PSK / TKIP, WPA-PSK / AES modes and found a significant throughput loss (24%) only in WPA-PSK / TKIP. All other modes had variation within the accuracy of my test methods. This is consistent with what I've found on other Broadcom-based products, and does put you at a throughput disadvantage if you mix the USB-G54 (or any other Broadcom-based client supporting WPA) with WPA-enabled APs or wireless routers based on GlobespanVirata (Intersil) or Atheros chipsets.

The best-case average throughput of about 20Mbps is consistent with Broadcom-based 11g products based on Ethernet or CardBus interfaces. So it appears that - unlike 802.11b USB1.1 adapters - you won't pay a throughput penalty for connecting via USB 2.

You will lose throughput, though, if you use the adapter with a computer supporting USB 1.1, as Figure 3 shows.

Figure 3: Throughput connected to USB 1.1
(click on the image for a full-sized view)

Smooths things right out, doesn't it? Although you wouldn't buy the USB-G54 specifically to attach to a USB 1.1-equipped machine, it's nice to know that you at least have the option.

802.11g Wireless Performance Test Results
Test Conditions


- WEP encryption: DISABLED
- Tx Rate: Automatic
- Power Save: Disabled
- Test Partner: Belkin F5D7130 Access Point

Firmware/Driver Versions

AP f/w:
2.00.01
Wireless client driver:
WinXP 5.1.3538.0
Wireless client f/w:
No Info

Test Description SNR (dB) Transfer Rate (Mbps) Response Time (msec) UDP stream
Throughput (kbps) Lost data (%)
Client to AP - Condition 1 0 20.4
[No WEP]
19.9
[w/ WEP]
1 (avg)
2 (max)
499 0
Client to AP - Condition 2 0 13.2 1 (avg)
3 (max)
499 0
Client to AP - Condition 3 0 2.8 3 (avg)
6 (max)
347 29
Client to AP - Condition 4 0 11.7 2 (avg)
3 (max)
499 0
See details of how we test.
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