New hard disk slows network speed...?

How odd is this one.

One of the hard disks in my main PC died, so I decided to move all my stuff onto a spare 500GB SATA drive (my PC is IDE-based) I had lying around.

I plugged my SATA drive into another PC using an IDE/SATA USB adapter off eBay - you can plug either SATA or IDE into one end, and the other end is USB. I noticed when I had it connected, the other PC's network speed would be drastically reduced - internet speed was about 2kb/s, and when I ran my ISP's speed tester, it had my upstream/downstream speeds as about 0.06kbps. I ran a few tests over a series of nights and had the same result.

I discovered that when I had the disk unplugged, internet speeds went back to normal (something like 7.6mbps). Literally, I would do a speed test, get 0.06kbps, then unplug the hdd, run another speed test and get 7.6mbps.


I've now moved all my stuff over to the new drive, and using an IDE/SATA converter board connected to the motherboard of my main PC (it just sits in the IDE slot, and presents a SATA port on the other end) have connected my 500GB SATA drive.

I just ran a internet speed test from my main PC and it comes back as having a max of 1750kbps - about 220kb/s. My other PC is sat right next to it, connected to the same router and if I run a test on that a minute later, I get 7.6mbps.

Why/how is the new hard disk affecting my internet speed? The PC isn't maxing out on I/O or CPU or anything, it just seems that the network speed is much slower.

Definitely a strange issue. What make and model of HDD is it?

It definitely seems to be the HDD itself causing this issue, so maybe their is a fault with the drive itself. I'm guessing this could be a grounding issue with its power supply. Have you tried grounding the casing of the HDD to the casing of the PC?

I had a similar issue a few years ago with a PC. As you are encountering, when connected to the network the whole lot would slow right down. Disconnecting it would return the rest of the network and PCs to normal. That turned out to be a faulty PSU that wasn't grounding correctly to the case.

I think it's a Seagate 500GB SATA. The drive itself works fine, it's just the network speed when it's in.

How do I ground it? It's screwed into the case in a 3.5" bay, so are you saying I need to jam a paperclip somewhere special between the HDD and the part of the case it's screwed into? So, the metal top part of the HDD case and the metal of the 3.5" bay?

The metal drive bay might not actually be grounded fully with the superstructure of the case. I would connect a wire from the metal casing of the HDD to somewhere on the chassis of the case, preferably part of the main structure, and see if that helps. It might not, but its worth a try to rule it out.

Have you also tried swapping the SATA cable being used? These can suddenly being faulty and cause strange behaviour.

It could also be an issue with the IDE to SATA converter you are using. I've had issues with these myself, either not working or losing drives during use... especially the USB to IDE/SATA adapters. Had a nightmare with one of those.