I used our standard open air test method described here to test the 2553's wireless performance. Testing was done using our standard wireless test client, an Intel Wi-Fi Link 5300 AGN mini-PCIe card in a Dell Mini 12 running WinXP Home SP3 and version 188.8.131.52 of the Intel drivers. I left all client-side defaults in place except for enabling throughput enhancement (packet bursting).
The 2553 was loaded with 1.0.6 firmware. All factory default settings were left in place, except setting channel 1 for the 2.4 GHz band and 36 for 5 GHz.
Figure 4 shows the IxChariot aggregate plot for all 2.4 GHz band downlink tests using 20 MHz channel width. Throughput variation isn't too bad, except for large dropouts in Location B, that pushed down its average throughput. The other plots can be viewed via these links: 2.4 GHz uplink- 20 MHz BW; 2.4 GHz downlink 40 MHz BW; 2.4 GHz uplink 40 MHz BW.
Figure 4: D-Link DAP-2553 wireless throughput - 2.4 GHz, 20 MHz mode, downlink
Figure 5 shows the IxChariot plots for the 5 GHz band tests in 20 MHz bandwidth mode. The other plots can be viewed via these links: 5 GHz uplink- 20 MHz BW; 5 GHz downlink 40 MHz BW; 5 GHz uplink 40 MHz BW.
Figure 5: D-Link DAP-2553 wireless throughput - 5 GHz, 20 MHz mode, downlink
The 2553 actually does pretty well against other tested dual-band products, especially running uplink. It tops the average throughput charts for dual-band products in both 2.4 and 5 GHz bands except for 2.4 GHz, 40 MHz mode. Maximum throughput was 92.9 Mbps running 5 GHz downlink in Location A in 40 MHz bandwidth mode.
I added only the DAP-1522 into the Wireless Location Performance Table along with the 2553 so that you can see what sort of performance the extra $40 or so buys you.
The Performance Table gathers all the average throughput test results for the selected adapters into a single table. It then highlights the highest throughput value in each Test location for each benchmark test. If results are within 1.0 Mbps of each other then both products' results are highlighted. Finally, the number of highlighted results are tallied for each test group and the product name with the most highlighted values is then highlighted.
Figure 6 shows that the 2553 does quite well, besting the DAP-1522 in all four cases. But note that the DAP-1522 was tested using a second D-Link DAP-1522 as the test client instead of the Intel 5300. So it's possible that the different clients account for some of the performance difference.
Figure 6: Wireless Performance Comparison Table - 2.4 GHz
Figure 7 shows similar results for the 5 GHz band. It also shows that the 2553 doesn't work miracles, since it was unable to reach test locations E and F, just like most other 5 GHz N products we've tested.
Figure 7: Wireless Performance Comparison Table - 5 GHz
I also checked that the 2553 properly limited connect rates to 802.11G's 54 Mbps maximum when using WEP or WPA-TKIP wireless security. Like all other N products, you need to run with no wireless security of WPA2/AES to access any link rates above 54 Mbps.
Use the Wireless Charts to further compare and explore the DAP-2553's performance.
If you're thinking that the DAP-2553's external antennas and higher price will buy you better performance than the DAP-1522, it looks like it probably does. But, like all 11n APs and routers I've tested so far, the DAP-2553 won't reach any farther if you're using it in the 5 GHz band.
However, given its extra features, ability to upgrade antennas, and average chart topping performance, if you have the money to spend, I'd recommend the DAP-2553 over the DAP-1522.