Cable Internet vs DSL: Which Is Actually Faster?

It's the perennial broadband question: should you go with cable internet or DSL? Both technologies deliver high-speed internet, but they work in fundamentally different ways — and that affects real-world performance more than the speed numbers in advertisements might suggest.

We've spent the last several months testing both types of connections in multiple markets to give you an honest assessment of what each technology delivers in 2007.

The Speed Numbers

On paper, cable internet wins the speed race. Here's what the major providers are currently advertising:

Cable internet (Comcast, Time Warner, Cox):

• Download: 6 to 16 Mbps
• Upload: 384 Kbps to 1.5 Mbps
• Most popular tier: 6 Mbps download

DSL (AT&T, Verizon, BellSouth):

• Download: 768 Kbps to 6 Mbps
• Upload: 128 Kbps to 768 Kbps
• Most popular tier: 3 Mbps download

Looking at those numbers alone, cable seems like the clear winner. But speed tests only tell part of the story.

The Shared Bandwidth Factor

The most important difference between cable and DSL is how bandwidth is delivered. Cable internet uses a shared network — everyone on your local node (your block or neighborhood) shares the same pipe of bandwidth. DSL provides a dedicated line from your home to the phone company's central office.

In practice, this means cable speeds can fluctuate significantly depending on the time of day. During off-peak hours — weekday mornings, for example — a cable connection often performs close to or above its advertised speed. But during peak usage hours, typically 7 PM to 11 PM on weeknights, you may see your speeds drop as your neighbors come online for streaming music, downloading files, and general browsing.

DSL speeds, on the other hand, remain more consistent throughout the day. Your connection doesn't slow down because your neighbor is downloading large files. The tradeoff is that your maximum possible speed is generally lower.

Real-World Testing Results

We tested cable and DSL connections in three markets over a two-week period. Here's what we found:

Morning (8 AM - 12 PM)

• Cable average: 5.8 Mbps (on a 6 Mbps plan)
• DSL average: 2.7 Mbps (on a 3 Mbps plan)

Afternoon (12 PM - 6 PM)

• Cable average: 5.2 Mbps
• DSL average: 2.6 Mbps

Evening Peak (7 PM - 11 PM)

• Cable average: 3.4 Mbps
• DSL average: 2.5 Mbps

Late Night (11 PM - 2 AM)

• Cable average: 5.9 Mbps
• DSL average: 2.7 Mbps

The pattern is clear: cable internet delivers higher peak speeds, but during prime time, the gap narrows considerably. In our tests, the cable connection sometimes dropped to speeds comparable with or even below the DSL connection during heavy evening usage.

Distance Matters for DSL

There's another factor that doesn't show up in speed tier comparisons: DSL performance is heavily dependent on how far your home is from the telephone company's central office. Copper phone lines lose signal strength over distance, so users close to the central office get the best speeds, while those farther away get slower service.

If you're within about a mile of the central office, you'll likely get speeds close to what's advertised. At two miles, expect some degradation. Beyond three miles, the connection may be significantly slower than the plan's top speed, and at around three and a half miles, DSL may not work at all.

Cable internet doesn't have this distance limitation — the signal is amplified at regular intervals along the cable network.

Reliability and Uptime

Both technologies are generally reliable, but they fail in different ways:

• Cable is more susceptible to neighborhood-wide outages. If a cable node goes down, everyone connected to it loses service. However, individual connection drops are uncommon.
• DSL is more susceptible to line quality issues. Old or damaged copper wiring, moisture in junction boxes, and distance-related signal loss can cause intermittent problems. But since it's a dedicated line, your neighbor's issues don't affect yours.

In our experience, both technologies deliver uptime in the 99+ percent range for most users. Major outages are rare with either.

Pricing Comparison

As of spring 2007, here's what typical broadband service costs:

| Service | Speed | Monthly Price | |---------|-------|---------------| | DSL Basic | 768 Kbps | $14.99 - $19.99 | | DSL Standard | 1.5 - 3 Mbps | $24.99 - $32.99 | | DSL Premium | 6 Mbps | $34.99 - $44.99 | | Cable Standard | 6 Mbps | $42.95 - $52.95 | | Cable Premium | 8 - 16 Mbps | $52.95 - $62.95 |

DSL is generally cheaper, especially at the entry level. Many phone companies are aggressively pricing DSL to compete with cable — AT&T's basic DSL starts at $12.99 per month for the first year.

Which Should You Choose?

Here's our recommendation based on usage patterns:

Choose DSL if:

• You want the most affordable broadband option
• Consistent speeds matter more to you than peak speeds
• You live within a mile or two of the phone company's central office
• You're a light to moderate internet user (web browsing, email, occasional downloads)

Choose cable if:

• You need the fastest available speeds
• You do a lot of downloading or plan to use bandwidth-intensive applications
• You don't mind occasional slowdowns during peak hours
• DSL is unavailable or very slow at your address due to distance

For many households in 2007, the honest answer is that both work perfectly well. A 3 Mbps DSL connection handles web browsing, email, and music streaming without breaking a sweat. If you want to future-proof a bit — or if multiple computers in your home are online simultaneously — cable's higher ceiling gives you more headroom.

Looking Ahead

Both cable and DSL providers are working on faster technologies. ADSL2+ could push DSL speeds to 12 Mbps or more for users close to the central office. Cable's DOCSIS 3.0 standard promises speeds of 100 Mbps and beyond. And fiber-optic services from Verizon and others are beginning to roll out, promising even faster speeds.

For now, either cable or DSL will serve most households well. The best choice depends on your specific location, usage needs, and budget.