Asset ID:	1-71-1018046.1
Update Date:	2009-10-14
Keywords:

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Solution Type  Technical Instruction Sure

Solution  1018046.1 :   PCI Performance Considerations in a Sun Fire[TM] V20z  


PreviouslyPublishedAs
229352

Description
The AMD 8131 PCI chip splits into two buses or "branches", over which it communicates with onboard devices and external PCI components. The 2 branches are named A and B. Branch A is 66MHz and Branch B is 33MHz.

The 66MHz/64-bit PCI slot shares the same branch, Branch A, with the two on-board GigaBit Ethernet connections and the U320 SCSI RAID controller. Careful choice of where PCI cards are installed in the V20z can optimize I/O performance.

Steps to Follow
1) If you are using the on-board GigaBit Ethernet connections and one PCI card, install the PCI card in PCI slot 2 (full-length).

2) If you are using the on-board GigaBit Ethernet connections, and two PCI cards, install the faster PCI card in PCI slot 2 (full-length), and the slower card in PCI slot 1 (half-length). Note: If installing a 33MHz PCI card into PCI slot 1, branch A, will operate at 33MHz.  This will affect I/O  performance.
3) If you are not using the on-board Gigabit Ethernet connections, install a half-length card in PCI slot 1 and a full-length card in PCI slot 2.
Use only +3.3 V PCI cards in your Sun Fire[TM] V20z.
Do not use +5 V PCI cards or it will cause damage.
Slot 1 is the 66MHz PCI slot; branch A.
Slot 2 is the 133MHz PCI slot; branch B.

Product
Sun Fire V20z Server
Sun Fire V20z Compute Grid Rack System

V20z, Stinger, PCI, performance
Previously Published As
79531

Change History
Date: 2005-01-20
User Name: 25440
Action: Approved
Comment: Excellent clarification. I've moved the explanation of the term "branch" to be the first item in the Description section (before the first mention of the term), however. The explanation did state that Branch B was 133MHz (one hundred and thirty three) – from the context of the rest of the document this is a typo and should read "33MHz". I've changed it. Publishing.
Version: 6
Date: 2005-01-18
User Name: 125738
Action: Approved
Comment: I have added an explanation for "branch" in my draft. Please review.
Version: 0
Product_uuid
1acc55b3-4b82-11d8-99fc-080020a9ed93|Sun Fire V20z Server
e8f8b6a9-7393-11d8-9e3a-080020a9ed93|Sun Fire V20z Compute Grid Rack System

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