Pre-launch, Telecom boss Paul Reynolds claimed that a song could be downloaded over XT in 13 seconds.

This morning, using a Sierra Wireless 885u USB stick for XT ($399; a data card version costs $199), Keallhauled was able to down a 5MB song in 15 seconds.

No doubt that two second discrepancy will have some rivals screaming “Reynolds is a LIAR!” in our Comments section, as per usual, but like XT’s overall mobile data performance, it’s a solid result.

Wandering Auckland’s CBD, with the USB modem attached to a Lenovo Ideapad netbook, I was able to clock download speeds of between 1.4Mbit/s and 2.73Mbit/s.

That compares to a the peak speed Vodafone Vodem USB modem speed I’ve registered of 1.9Mbit/s (which was back in September). And the fastest I've clocked Telecom's T-Stick, which runs on its old CDMA netork, is around 0.5Mbit/s.

Others have clocked up to 3.6Mbit/s on XT, and you can squeeze more speed if you turn of all other internet apps, such as instant messaging and Skype, and tweak your operating systems comms settings. NBR preferred to test a regular, everyday experience.

Like Vodafone 3G (and the coming Two Degrees network) Telecom’s XT has a theoretical top download speed of 7.2Mbit/s. However, the vagaries of any cellular connection, anywhere - including how close you are to the nearest cell tower, how many obstacles are in between, the traffic-load on that cell tower, the quality of local backhaul from the tower etc etc - mean you can reasonably expect to hit about half the rated top speed.

By this measure, XT is performing capably. I do have the benefit of being one of only a handful of users so far. We’ll see how things shape up over the coming months as this particular data highway starts to fill with more traffic.

I clocked 2.73Mbit/s connecting to a New Zealand-based server (at speedtest.net).

Trying the same test from a server based in Australia, top speed dropped out to around 1.8Mbit/s.

Downloading data from the east coast of the US, it dropped again to 1.1Mbit/s (in terms of those so-so star ratings in the screen grabs, note that most benchmarks in the SpeedTest.net data base are for DSL or cable connections).

Again, there’s no surprise there; landline connections slow by a comparable amount when you tap international sites, which inevitably involve several weak links in the data chain.

Latency (lag) was not enough to slow multimedia. I was able to watch tvnzondemand videos and others as smoothly as on my landline DSL connection.

But, as with any wireless, internet connection, the lag was still too great for, say, heavy-duty multiplayer internet gaming.

Hitting download.com in the US, I pulled down the most popular file over XT - the 62MB freebie antivirus programme AVG. It took about five minutes, with XT maintaining consistent speed.

Fast downloads, slow price movement
I’d have no problem using XT for larger mobile data downloads, even it wasn’t Telecom’s pricing which, like Vodafone's, remains relatively steep compared to Australia and elsewhere..

At Telecom’s investor briefing yesterday, a questioner from the floor asked if XT would get so fast (and an upgrade to 21Mbit/s and faster is on the way) that it would start to Telecom’s DSL landline business.

Head of retail Alan Gourdie replied that there could be some cannibalisation, but it would be limited as Telecom rolled out faster landline products (such as its VDSL2 upgrade coming later this year), keeping DSL head (and way ahead in latency).

However, with Telecom and Vodafone (and, seemingly, even Two Degrees’) mobile data pricing so much higher than landlines, and twice the cost of Australia or Sydney, simple economics dictates that most users will prefer DSL.

That said, XT mobile data is clearly capable, and if you steer clear of huge downloads, it won’t break your bank balance (Telecom is charging $54.95 for 1GB/month, or $5 more than Vodafone, and $84.95 for 3GB/month to Vodafone's $69 to $79/month depending on plan).

Mr Gourdie says Telecom wants to increase the number of its customers regularly using mobile data from 5% to 20%, and double its number of mobile data devices to 185,000 in XT’s first year. By my experience today, he’s got a good shot.

Incidentally, the Sierra Wireless 885u USB was easy to install. Like other data dongles from Vodafone and others, it sell installed its software after I plugged it in, and getting online was as simple as clicking a connect button.

Like the Vodem, the Sierra Wireless 885u it takes a SIM card, and has bundled software for managing contacts, or sending txts, from your PC.

A microSD slot can take a memory card of up to 4GB, on a bring-your-own basis.

Speaking of BYO, I did have to rope up a Lenovo netbook myself. Telecom needs to get netbook and laptop embedded 3G deals happening, a la Vodafone's hook-up with Dell.

Voice performance
In terms of voice performance, I've been using XT with a Nokia 71 and Nokia 95 for several days now. Call clarity on both has been fine, with no drop outs or other problems. I doubt if, in a blind test, anybody could pick between XT and Vodafone 3G; both are running on essentially the same 3G technology, and again the usual vagaries of distance, traffic etc apply.

In short, XT's performance is fine. It's broader competitiveness, and success, is going to be shaped by factors like pricing, bundling with other Telecom services, and the Hammond campaign (personally, with the delayed launch, I've already reached my limit of Hamster tolerance and race for the remote when he appears).

Below, for the benefit of the Comments crowd, a command line ping to what I'm assured is a most popular site, nbr.co.nz: