I have this peculiar problem on an [HP Pavilion DV7-5000](http://h20424.www2.hp.com/campaign/consumer_notebooks/ap/en/resources/dv7-new-brochure.pdf) (product number XE385EA) that can hang the system for a few moments—up to 10 seconds sometimes—if the application reads from the disk and it was occurring since the beginning. The disk LED is on when it happens. It also does not appear to hang the OS itself, but the application that reads from it:

* It happens on videos that are read from the internal HDD and not if they are read from an external USB drive. The video hangs as well as the audio and it resumes later. The rest of the OS does not appear hang completely, but applications such as browsers also “pause” momentarily.
* It happens on games installed on the internal hard drive. Not on games installed on an external USB drive.
* It happens on browsers and other applications that are installed on the internal HDD.

Relative models of the [HP Pavilion DV7-5000](http://h20424.www2.hp.com/campaign/consumer_notebooks/ap/en/resources/dv7-new-brochure.pdf) had a SATA problem so they were eligible for replacement. But I heard that did not apply for the `HM55` chipset and it appears this model has the HM55 chipset so I assume it’s not that problem.

I have searched for “thrashing” and `HM55` and I don’t see anything definitive. Or with “pause” `hm55`.

The problem appears also on completely different operating systems (Linux, Windows 7 and Windows 8) so it appears closer to hardware, though you never know if both have the same software problem.

I wonder if a new internal disk would fix it or it's a controller problem?

The problem is that the laptop does not have a 2nd slot for a disk (not even connections) so one can’t just add a second disk.

I have some limited programming knowledge and this reminds of an `fread()` hanging a single-loop app, but in a deeper hardware sense since it occurs on apps that provide for that.

The disk/controller from CrystalDiskInfo:

```
-- Controller Map ----------------------------------------------------------

 + Intel(R) Mobile Express Chipset SATA AHCI Controller [ATA]

   - ST9500420AS

   - hp CDDVDW TS-L633R

```

Seeing that, I wonder if disabling the CD will fix it. I doubt it, but I may try it.

As far as what I have tried to attempt to solve the issue, with both caching options selected the problem is alleviated (both boxes ticked in the relevant device manager properties page for the drive). It still occurs but it’s more rare and it appears to last for fewer seconds. With caching options disabled (both caching options unticked in device manager for the drive) it occurs much more frequently.

It doesn't appear to be much different between normal and safe mode, though it may be related to frequency of operations/activity in general of writes or reads.