Can 7200/5400rpm Hard Drives be used together

  User-498DB432-30A7-4FC5-B65F3A4738DB7CB4 13:41 06 Jun 2003

Hi, at the moment I have 2 40Gb 5400rpm HDD & I am going to buy a HDD controller card.

I want to know if I can use both HDD speeds in the computer ie: 2 that run @ 5400 rpm & another running @ 7200 rpm as someone told me it will not work.

Thank you.

  TBH1 13:51 06 Jun 2003

they will work together

  Bailey08787 13:51 06 Jun 2003

you can as long as you hook them up using different cables to connect them

otherwise i believe the 7200 will drop down to the 5400rpm.

I'm curious whether this applies to cachme levels too? As I have one drive with 2mb cache, and another with 8mb cache - will it be affected if they're hooked up to the same ide cable?

  Megatyte 14:14 06 Jun 2003

With modern IDE controllers mixed drives on the same bus will each run at their respective speed(i.e. a 5400 rpm will not pull a 7200 rpm down).


  eccomputers 14:17 06 Jun 2003

I didnt realise the rpm had anything to do with the cable? surely this speed is built into the hard drive and it isnt powered by the ribbon cable. The rpm doesnt govern the transfer rate. Can someone confirm if this is true as I was obviously misinformed somewhere?

  drummerdude436 14:18 06 Jun 2003

Why just try running the 5400 as a secondary master rather than a primary slave? obviously if you've only got the two IDE slots on your mother board, you will lose your CD drive or anything else in the second slot.
Just an idea though....

  Megatyte 14:23 06 Jun 2003

You are correct. Mixed drives on the same bus will each perform to to their respective specifications (provided that an 80 wire cable is used and ultra DMA is supported if applicable.


  eccomputers 15:02 06 Jun 2003

drummer, he wouldnt lose the cd on the secondary channel. You simply move the jumper to slave.

  drummerdude436 15:04 06 Jun 2003

ah, yes
sorry, overlooked that!!!! unless hes using two CD drives that is


  SEASHANTY 16:12 06 Jun 2003

A HDD controller card such as those made by "Promise" will give you an extra two EIDE controllers when fitted in a spare PCI slot. Just be aware that Hard Drives on initial startup take about 1.5 amps from the power supply. You can arrange to stagger the startup times with multiple drives but it may also be advisable to uprate your PSU unit to 450 watts or even 550 watts.

  BillEmm 22:32 06 Jun 2003

Sorry SEASHANTY, I ran three drives off a Promise IDE 133 PCI card on a system that only had a 250 watt PSU. I would agree that something akin to 350 watts would be more realistic but 550 is over the top.

I do concur with your point about spinup drawing more power. This can be as much as twice the normal running power requirement and does place quite a strain on the PSU. A 7200rpm can require up to 24 watts on spinup.

What has been missed in all of the above is the extra heat that the 7200rpm drive will create and this will need dissipating. The web is littered with stories of new 7200 drives failing early - simply because additional disk/case cooling was not considered. These drives get very hot and should not be placed adjacent to another heat source without extra ventilation.

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