Please note that all iPod models mentioned in these Q&As have been discontinued.

What is the difference between the third and fourth generation iPod models?

The fourth generation iPod, introduced July 19, 2004 and discontinued June 28, 2005, originally shipped with either a 20 GB or 40 GB hard drive, and from February 23, 2005 to June 28, 2005 shipped with just a 20 GB hard drive.

The fourth generation is similar to the third generation models, but features a slightly thinner enclosure and an improved display, borrows the revolutionary "ClickWheel", which places pressure sensitive navigation buttons under the scroll wheel, from the previously introduced iPod mini, and dramatically improves battery life for up to 12 hours of continuous music playback.

In addition to improving battery life, revised software places the "Shuffle Songs" feature on the main screen, and includes the voice record feature, games, and an alarm clock from the third generation model. The original 40 GB configuration of the fourth generation shipped with a "dock" for quick-and-easy connection to a computer and could be purchased separately for the 20 GB configuration. Like the third generation models, the fourth generation of the iPod also has 25 minutes of skip protection.

Also see:

• What capacity and type of hard drive does each iPod and iPod mini use?
• What is the "Clickwheel"? How is it different from the "Thumbwheel"?
• How can I use my iPod as a voice recorder?

What is the difference between the Apple iPod & HP (Hewlett-Packard) iPod?

There is extremely little difference between Windows-compatible Apple iPods and the corresponding models that were offered from Hewlett-Packard. Each are identicial except HP added an HP logo below the Apple logo on the back of each player and shipped their models in a box that matched the design of other HP products.

Hewlett-Packard offered the following iPods under their name:

• iPod 4th Gen (ClickWheel)
• iPod photo (30 GB)
• iPod photo (40, 60 GB)
• iPod "Color" (20, 60 GB)
• iPod mini (2nd Gen)
• iPod shuffle

On July 29, 2005, HP announced that it would no longer ship HP-branded Apple iPods as it did not fit with their "current digital media strategy". For more information, please refer to "How to Determine if you Have an HP iPod" from the Apple Support Site.

What is the difference between the fourth generation iPod & iPod photo?

The iPod photo models are substantially different from the fourth generation iPod. Upon first glance, the iPod photo models look about the same, as they use a similar "iBook white" and stainless steel case and have a "ClickWheel", which places pressure sensitive navigation buttons underneath the scroll wheel. However, one quickly notices that iPod photo models have a two inch color backlit LCD display (220x176), compared to the two inch grayscale blue-white backlit LCD display (160x128) used by the iPod 4th Gen.

The iPod photo software is similar to that used by the iPod 4th Gen, but adds color to all interface elements and applications, uses a new font called "Myriad", and as the name implies, supports viewing photographs, optionally with synchronized music, both on the internal display and on a television or projector using the included AV cable via the custom headphone jack that is capable of video output (line out and S-video provided by the dock, which along with the AV cable, was sold separately after February 23, 2005).

The iPod photo also improved upon the already solid battery life of the fourth generation model, and can provide up to 15 hours of music playback or up to 5 hours of slideshows with music.

The iPod photo shipped with 40 GB and 60 GB hard drives from October 26, 2004 to February 23, 2005 and 30 GB and 60 GB hard drives from February 23, 2005 to June 28, 2005. From June 28, 2005 to October 12, 2005, Apple shipped 20 GB and 60 GB models with color displays and photo capabilities named simply iPod Color Display (20, 60 GB).