Will 66MHz cards work in 33MHz slots?

[Jordan_29]

Hi guys,

Hopefully a simple question:

I have a ML570G1 and this machine has only two 64bit 66MHz PCI slots and the other four are 64bit 33MHz PCI.

It currently has one array controller in it. What I need to add to it are two fibre channel HBAs and two dual channel gigabit NICs. Thanks to everyone on the forum - I have the models I would like in mind. However, it seems that all the cards I am after specify that they are for 64bit 66MHz slots and not implicitly for 64bit 33MHz slots.

- The NICs I want are the NC3134 with NC7132 upgrade module
- The HBAs I want are the FCA2101

Given I have only two 66MHz slots and potentially four 66MHz cards (not sure what slot the array controller is in yet) then if they will not run at 33MHz then I have quite a large issue on my hands. Ive not purchased anything yet but I need to soon (and to make matters more expensive, I actually have two ML570G1's to upgrade!)

Any help would be much appreciated.

Cheers
Jordan

[Tv_3 · Accepted solution]

Hi, Jordan,

A 33MHz card may be plugged into a 66MHz slot but will not get any performance benefit from being in a 66MHz slot. Doing so will slow down the PCI bus such that both slots on the same bus will operate at 33MHz, potentially harming the performance of a 66MHz device in the other slot. A 66MHz card may be plugged into a 33MHz slot but will have reduced performance, as it will operate at 33MHz.

sincerly...
Tmy

[Jordan_29]

That you so much for your reply.
I was hoping that was the case, and yes, I fully expect it to drop back to 33MHz. As long as they work at all I will be happy. These machines are getting relegated to development and print serving so performance will not be a huge issues as opposed to the production machines. Our entire network infrastructure has been upgraded and gigabit and fibrechannel are accross the board for all servers - so its really nice to know that I can get the G1's up to scratch for this. I was also aware that both slots on that bus will drop back - its good to have someone else confirm this before I spend a bundle on NICs and HBA (as my neck would be on the line if they didnt work).

Cheers
Jordan