I purchased the 4109na version of this laptop (same machine with a few different specs) because it has excellent specifications. Unfortunately, it started to emit a strange electrical sputtering sound from the keyboard over the CPU area. The sound was very faint, but noticeable in a quiet room. It's not the fan because it's constant from the start even when the machine is cold. I sent it back to HP twice to fix the issue and they sent it back to me stating it is normal and within specification - in other words, it makes a faint, but constant noise as normal. I wasn't happy because I know that solid state devices (excluding the fan) do not make any noise at all. HP refused to refund the product because I had owned it for 6 weeks longer than the prescribed one month return period. They refused to change any of the components either to see if that might have made a difference and told me there was nothing they could do. This has cost me and them a lot of time, but they won't budge on their policy.
I asked HP to confirm if it was normal for HP products to make strange electrical noises as part of their specification, but they refused to comment on this. The (outsourced) repairer however, did confirm that it makes a faint noise and compared it to another machine of the same specification confirming that the noise was the same indicating that this is normal.
To put into context, imagine if your iPad or MacBook Pro made faint, but constant electrical sputtering noises from the CPU area. You would automatically think that your machine was defective. The Apple build quality is very high and this would never be acceptable. HP are essentially saying this noise is acceptable.
Nice specifications, nice-looking machine, but beware of the build quality. HP have never really had a great reputation for build quality and I suppose this proves it. I naively thought they might have improved over the years, but I was wrong. Do your research first. I'm now stuck with this machine and HP have dug their heals in by refusing to acknowledge they might have build quality issues. They continue to quote 'it is within specification'.