Rfi

[Mictlantecuhtli]

Has anyone experienced problems caused by RFI? I had this weird problem (I think it's because of RFI): When my IDE cable was not shielded, transfer rate was about 400kb/sec (UDMA/100). But when I wrapped the cable and hdd into those plastic shielding bags (non-conductive), the speed went back to 27 Mb/sec.
The cable was included in my motherboard package and it works, I've checked it.

 

[ToRN]

mmm, seems interesting. Sure it is because of the RFI? How did you measure?

 

[Mictlantecuhtli]

I don't have anything to measure it with, but I figured it's because of that. I have no idea what else it could be. Or is it this hdd - Samsung Spinpoint SV4084H?

 

[Per Hansson]

Aren't IDE cables already shilded?

 

[Mictlantecuhtli]

Define "shielded". Every other wire is ground, AFAIK, but the whole cable itself isn't shielded.

 

[Mictlantecuhtli]

With additional shielding:

hdparm -tT /dev/hda

/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.53 seconds =241.51 MB/sec
 Timing buffered disk reads:  64 MB in  2.56 seconds = 25.00 MB/sec

Without:

hdparm -tT /dev/hda

/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.53 seconds =241.51 MB/sec
 Timing buffered disk reads:  64 MB in 15.30 seconds =  4.18 MB/sec

This time it didn't drop that much, but it's still very annoying.

 

[Per Hansson]

Hmm, that seems strange; The information read from the cache isn't affected but the one from the platters are

That seem very wierd since it's the info going from the harddrives cache that goes at insanley high speeds (It could actually hit the ATA standard your HD supports I.E 100MB...)

But when the data is read from the platters it takes an eterninty to get it moving...

Strange indeed!

But as long as it's working for you...