Which is the preferred (more powerful) USB port on my new (early 2015) MacBook Pro?

None are more powerful, the power specification for USB ports includes all USB ports.

What makes you think that things don't matter? they need power and unless you are giving it to them some other way they are getting it via the USB port. Is there enough?

Then you have no problem. You already know what to do, an article told you.

I agree with Csound1 when he says none are more powerful. From the specs for the Macbook Pro (http://store.apple.com/us/buy-mac/macbook-pro)

Connections and Expansion	15-inch model shown MagSafe 2 power port Two Thunderbolt 2 ports (up to 20 Gbps) Two USB 3 ports (up to 5 Gbps) HDMI port Headphone port SDXC card slot Apple Thunderbolt to FireWire Adapter (sold separately) Apple Thunderbolt to Gigabit Ethernet Adapter (sold separately)

What specs are you referring to when you say "Well in my specs it says one is a hi speed USB bus and one is super speed."?

I've heard that this issue of having differently powered USB ports exists in the Mac mini due to posts of users with problems connecting a high-power device such as an iPad and the device showing the "not charging" message on the iPad. Plugging into a different USB port on the mini usually fixes this issue.

That being said, I've never heard of differently powered USB ports on any MacBook and have seen no such thing on my MacBook Pro (Late 2011) either.

SergZak wrote:

I've heard that this issue of having differently powered USB ports exists in the Mac mini due to posts of users with problems connecting a high-power device such as an iPad and the device show the "not charging" message on the iPad. Plugging into a different port usually fixes this issue.

That being said, I've never heard of differently powered USB ports on any MacBook and see no such thing on my MacBook either.

USB ports have to conform to the USB spec, they all provide the same output (if they are of the same type) USB 2 can supply 0.5 amp, USB 3 0.9 amp, dedicated charging only ports (of which there are none on an MBP) can supply 1.5 amp. These are continuous figures, not peak.

The ports are the same, the article the OP read is junk.

Agreed. It could also be that the "dongle/Soundcard box (Serato SL3)" that the OP is using is simply demanding more power than the ports are spec'd for or can supply...due to improper design or maybe even a hardware fault in the dongle itself.

The specs for the Rane SL3 state "Power Req: 400 mA, 5.0 Volts" from the website here:

http://serato.com/hardware/rane-sl3

So any USB 2.0 port should provide more than enough power. It also appears that it uses it's own power supply as well and is not solely powered by the USB port.

My son is a successful DJ, and a Serato user (although he uses the SL4 rather than the SL2) it is bus powered and consumes 500Ah, an easy task for any USB port unless many other devices share the same bus. he just came back from a China/Japan tour, carrying 2 MBP's and 2 SL4's, external + bus power all the way. The SL4's were connected to external rather than bus power.

DJSleepyT wrote:

I'm also using a Denon USB Controller and turntables with a pioneer mixer, but I dont think any of that matters. The USB powers the Serato box that is plugged in.

Are you powering everything that is USB powered from the MacBook's USB port? If so, you could very well be maxing out the port's capability to provide ample power.

I'm trying to figure out the same thing on my retina. It's not about how much power, it because one of the usb ports is actually in a hub with the laptops keyboard, trackpad and i-sight camera. If you plug an multi-channel audio device in such as a rane sl3, you can get usb dropouts if you use the one that is on the internal hub. I'm not sure if its like this on the retina, but if I do it on my older unibody I get latency issues and audio dropouts.