Thunderbolt vs. USB 3.0

Kaya Systems

Thunderbolt and USB 3.0 go head-to-head

Intel’s Thunderbolt has arrived on the PC after being exclusive to the Macintosh platform for more than a year. With its promise of 10Gb/s‑per‑channel throughput, what self-respecting power user wouldn’t opt for a Thunderbolt-based external backup solution? Well, before you get too excited, let’s compare T-bolt point-by-point with its natural competitor, USB 3.0 . After all, there’s more to a technology than pure performance, as we found out.

Round 1: Specsmanship

Intel created USB in the 1990s, and it has been an amazingly revolutionary technology. USB has scaled from 12Mb/s at its inception to 5Gb/s today with relatively minor road bumps, and is now basically “free,” as it’s included on Intel’s and AMD’s chipsets. Still, when you play the specsmanship game, it’s hard not to fall in love with Intel’s newest child: Thunderbolt. SuperSpeed USB 3.0’s theoretical 5Gb/s, or 640MB/s, looks impressive until you notice that Thunderbolt can move 10Gb/s over its copper interface. Oddly, the 10Gb/s speed is actually a misrepresentation. Thunder­bolt can move 10Gb/s per channel. Since it has two channels, it can actually hit 20Gb/s. That means Thunderbolt theoretically moves 2.5GB/s if you don’t account for overhead. Why not call it 20Gb/s? Intel doesn’t want to brag, apparently.

Winner: Thunderbolt

The Promise Pegasus R4 RAID cabinet offers blistering speed—if you have a Thunderbolt port and $1,000.

Round 2: Price

You know what’s incredible about USB 3.0 today? It’s practically free. It comes baked into chipsets from both AMD and Intel , and even when it’s not native, host controllers cost just two bucks. Thunderbolt’s pricing, on the other hand, is crazy expensive. At least we think so; we don’t know how much the controllers—all made by Intel—even cost. Early on, one vendor told us $200, which is insane. Other board makers have since told us that T-bolt chips cost about $30. Whatever the cost, the fact is that basic boards with Thunderbolt cost about $60 more than similar boards without it. Let’s not even get into the cables, which today cost $50 for a basic 2‑meter span. By a country mile, USB 3.0 wins this category, and we can’t see that changing for the foreseeable future. Did we mention that Thunderbolt cables cost $50?

Winner: USB 3.0

Round 3: Ubiquity

USB ports are so common, they’re in cars and wall plugs and are as ubiquitous as an AC outlet these days. Have to bring a boatload of data to your friend’s house? Just unplug your USB 3.0 cabinet and bring it with you. Even if he doesn’t have USB 3.0, you can still access your data via USB 2.0. That’s not the case with Thunderbolt, which is extremely rare even on the Macintosh platform, where it’s been supported for more than a year. If you want to lug your project on your Thunderbolt drive to your friend’s house, you’d better bring your computer too, because he or she likely doesn’t have Thunderbolt. Hell, by the end of 2012, Intel is hoping that we’ll have 100 devices that support Thunderbolt. There are likely 100 USB 3.0 devices made in just burnt umber alone.

Winner: USB 3.0

Round 4: Implementation

Why is Intel wielding iron-fisted control over Thunderbolt instead of releasing it to the world? We believe the company is trying to fast-track the technology by using a unilateral approach to bypass the usual rule-by-chaos that’s so common to committee-driven standards. Look at Bluetooth, Wi-Fi, and even early USB adoption as examples: Incompatibility raged for years. Even so, Thunderbolt isn’t perfect. We could not hot-plug our Thunderbolt device without hardlocking the system. So, epic fail? Not really. USB 3.0 really hasn’t been smooth-as-silk, either. Coaxing the highest performance out of USB 3.0 is not easy. And with more than a half-dozen USB 3.0 host-controller makers, the performance and reliability can be irregular. Even the board we used for our performance tests, Asus’s P8Z77-V Premium , gave us two USB 3.0 controllers, each with its own modes to enhance speed.

Winner: Tie

Round 5: Performance

Let’s be frank: It’s hard to make a definitive judgment about the performance of either the Thunderbolt or USB 3.0 interface based on our speed tests alone because of all the variables inherent to the hardware. Even so, it’s obvious to us that Thunderbolt is wickedly fast. The ATTO benchmark clocked the Promise Pegasus R4 reading files in the 936MB/s range. We could literally copy 16.9GB of files to the R4 configured with SSDs in 23 seconds. Our gut says there’s likely a lot more headroom left in Thunderbolt, too. USB 3.0 didn’t impress us as much. The Startech cabinet was allergic to our OCZ SSDs. Performance wasn’t stellar, but it wasn’t horrible either. USB 3.0’s speed is actually very respectable, but Thunderbolt clearly has the edge in pure performance.

Winner: Thunderbolt

If equipped with the same four 1TB drives, the Startech USB 3.0 RAID Tower would cost about $780 but would let you run the ubiquitous USB 3.0.

And the Winner Is…

Yeah, we know, no one likes a tie, but to recommend one technology over the other at this point would be wrong. If you need performance external storage for video editing, photo editing, or other storage-intensive needs, Thunderbolt rules. It’s over, right? Hands down, performance wins? Not quite. Ubiquity really matters in this world. As we said earlier, the inability to just grab your data and go to work at a friend’s or colleague’s without wondering if Thunderbolt is available is a major ding. Thunderbolt pricing is also at a premium, but really not quite as over-the-top as we expected. We acknowledge that T-bolt has other interesting configurations, but we think its primary purpose today will be for storage.

One thing is clear: The showdown between USB 3.0 vs Thunderbolt isn’t over. And as much as their respective proponents deny that the two interfaces even compete, we think both are headed for a major clash down the road.


Promise R4 w/4 SSDs in RAID 0 on Thunderbolt Promise R4 w/4 HDDs in RAID 0 on Thunderbolt Startech w/4 HDDs in RAID 0 on USB 3.0
CrystalDiskMark 3.01 Read / Write (MB/s)
402 / 540 357 / 500 267 / 247
AJA Video Systems Benchmark Read / Write (MB/s)
622 / 732 508 / 685 255 / 227
ATTO Disk Benchmark Read / Write 8MB file (MB/s)
939 / 831 936 / 417 265 / 254
Time to write 16.9GB of data (sec)
55 110

Best scores are bolded. Our test system used an Asus P8Z77-V Premium board with a Core i7-3770K, 32GB of DDR3/1600, Windows 7 Professional SP1, on a WD 150GB Raptor. Four 1TB Hitachi HDS72101 HDDs were used to test the Promise R4 and Startech USB 3.0 RAID enclosures. The Promise R4 was also tested with four OCZ 240GB SATA 6Gbs SSDs in RAID 0. File-write performance copied 16.9GB of Steam games from a 26GB RAM Disk with 5GB/s read speeds.

NOTE: This article was taken from the November issue of the magazine.

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