Apple's latest flagship iPhone is selling at a record pace but widespread reports of problems with the phone's internal motion sensors could spell trouble for Cupertino. Many are claiming the accelerometer, compass and gyroscope in the iPhone 5S are extremely error-prone but whether or not it's a hardware issue or something that can be solved with a software update remains to be seen.

Gizmodo recently tested two iPhone 5S units running the latest version of iOS 7. When compared against the iPhone 5 and real-world measuring tools like a level, they found the 5S' were embarrassingly inaccurate.

It may not sound like a huge deal but it could cause a lot of problems. For example, when using a level app like iHandy Level to hang shelves or picture frames, you're going to end up with a terrible looking project. More common, perhaps, is the fact that it will also cause issues with games that use the gyroscope. When placed on a flat table, the publication found the steering in EA's Real Racing 3 to veer to the left. Oops.

The issues seemed to persist with the Compass app as well. When getting steady readings, the iPhone 5 and iPhone 5S were consistently about 8-10 degrees apart. Furthermore, the Compass app on the 5S often crashed or gave wonky readings that were only remedied by killing and restarting the app.

Some speculate that because the issues aren't present in the iPhone 5 with iOS 7, the incident could be hardware-related. Specifically, the devices might not have been calibrated correctly from the factory and if that's the case, there are potentially millions of faulty devices in the hands of Apple customers.

We'll keep an eye on this and see if Apple publically addresses the issue in the coming days or weeks.