IBM IntelliStation POWER 285
System Type: 9111
Released in 2005 this system used POWER 5+ and was built around the System p5 520 tower with CAD friendly options enabled; along with extensive foam to reduce vibrations and noise as these would reside in an office or cubicle with someone working nearby. IBM exclaims that these were even quieter than the previous generation which is tolerable but less than 'ideal'. It sounds a bit like a System x3300 M4 with a mechanical drone from vibrations due to the way the fans are mounted in the hotswap mechanism(!). I'm under the impression the noise was enough for IBM to sell the cheaper (and quieter) 185 models to corporate and government users. System p5 520 racks and towers both use the same motherboard: this is a practice IBM continuse today, but it's nothing unique: the early PC 300 desktops and towers used the same motherboard despite being in different form factors.
The IntelliStation POWER 285 could be fan-modded much like the x3300 M4 by the use of 'fan emulators' that connect to 12v, ground and the tachometer line. However, the thermal dissipation requirements between the two systems are vastly different, and it would be adviseable to only do it on a single-CPU model.
Out of the IntelliStation POWER systems remaining, this one probably remains the most publicly common due to the fact they're used as servers instead of CAD workstations. The size, age and austerity of the platform may help also drive these to lower costs and quicker distribution; few resellers want to hold onto such large products (these rival even some AS/400e towers). It's also the one with the most support from IBM, being the last to receive a firmware update and the last that will have extended support (2018).
--> Power5 System Firmware SF240_371 (Sep 7, 2010)
Due to IBM's licensing agreements I am not entitled to distribute the firmware update as it's licensed code. Therefore the above link redirects to IBM's Fix Central where it can be downloaded as long as you have a valid system serial.
--> IBM System p5 Express Announcement Overview - October 4, 2005
--> IBM IntelliStation POWER 285 RedBook Overview
--> IBM IntelliStation POWER 285 Express
--> Quick Start Guide for IntelliStation POWER 285
--> TAGITT-CATIA V4/ENOVIA DMU Evaluation
--> UNIX Workstations Facts and Features (2006)
--> System i & p PCI adapters (44 MB!)
--> System i & p fans
--> IBM IntelliStation POWER and IBM RS/6000 Graphics Performance Report
AIXAIX 7.2 Not Supported
Like the IntelliStation POWER 185, the GXT4500P and GXT6500P are not supported under POWER Linux. However, unlike the 185 no special procedures for Installing SUSE Linux Enterprise SLES 9 SP3 or Red Hat Enterprise AS4U3 due to the fact it doesn't use a PPC 970.
Server or CAD?
Because the conversion of the p5 520 resulted in the IntelliStation POWER 285 having a modified bezel and excessive foam, this means it's technically superior to a regular p5 520... since one was expected to sit in the same room with one of these computers. So it's probably more logical to seek out the IntelliStation variant as it goes to greater expense to contain the sound. And it uses what more people would consider a more stylish design.