This is an unofficial FAQ for the Opteron range of 64-bit CPUs produced by AMD. Opterons use AMD's AMD64 architecture (aka x86-64 or "Hammer").

Breaking News: Opteron Dual Core CPUs!

AMD have started demonstrating a 90nm dual-core Opteron CPU - follow this link for the official AMD anouncement - www.amd.com/us-en/assets/content_type/DownloadableAssets/040831_DC_presentation.pdf.

The good news is that the dual core Opteron:

• uses the same socket as the current Opterons (Socket 940);
• draws less than 95W;
• should run in most motherboards with only a bios upgrade; and
• will probably be launced at 2.4GHz judging by this review on an Italian website of a dula core engineering sample - www.hwupgrade.it/articoli/1193/index.html. The review is short an only contains one benchmark using Cinebench 2003 but amazingly the dual core opteron at 2.4GHz is slightly faster than two Opteron 250's in a dual processor machine.

AMD have demonstrated this by showing four dual core Opterons working in their 4-way reference system. HP have also demonstrated a 4-way dual core Opteron server ( h18004.www1.hp.com/products/servers/proliantdl585/index.html ).

The AMD roadmap ( www.amd.com/us-en/Processors/ProductInformation/0,,30_118_608,00.html ) also shows a dual core desktop CPU due out next year for Socket 939.

Breaking News: Intel Dual Core CPUs!

Not to be outdone by the AMD dual core Opteron demonstrations, Intel has demonstrated its own dual core silicon at the Intel Developer Forum. Although there have been rumours that what was demonstrated was a dual cpu machine not a single cpu dual core processor.

What Opteron processors are there?

The following Opteron processors are currently available (5/8/04). Pricing indicated below (in $US) is for customers purchasing direct from AMD in quantities of 1000 and above, and whilst not reflecting retail pricing, is is a useful yardstick for comparing the relative price of each processor.

What is the difference between 1xx, 2xx and 8xx series Opterons?

1xx series Opterons (140 ... 152) are suitable only for single processor operation.

2xx series Opterons (240 ... 252) are capable of operating as dual processors in motherboards which support two CPUs. 2xx series Opterons can also operate in single processor motherboards.

8xx series Opterons (840 ... 852) are capable of operating in quad or eight-way motherboards. 8xx series Opterons can also function in dual and single processor motherboards.

What nm process are Opterons made with?

Opterons are presently being made on a 130nm (0.13um) process but AMD have indicated that towards the end of year it will start making opterons using the 90nm process. At present (August 2004) only certain mobile Athlon 64 processors are being made at 90nm.

The die shrink from 130nm to 90nm should allow for higher clock speeds. Perhaps the Opteron 152, 252 and 852 will have 90nm cores.

Can I buy a couple of cheap (relatively) 1xx series Opterons and use them in a dual processor motherboard?

You may be able to use a single 1xx series Opteron in a dual (or greater) processor motherboard, but you cannot build a dual processor system by putting two 1xx processors in. 1xx series Opterons lack an additional hypertransport link required for interprocessor communication in dual configuration.

Is there a way to mod 1xx series Opterons so they can be used in dual processor systems?

Unlike Athlon XP processors (vis a vis their Athlon MP counterparts), there is no modification currently known which will allow two 1xx series Opteron processors to be used in a dual processor system. You are stuck with purchasing 2xx series Opterons if you want to build a dually.

Can I use a 2xx or 8xx Opteron in a single Opteron motherboard?

Yes, and the 8xx Opterons can also function in dual motherboards. See above "What is the difference between 1xx, 2xx and 8xx series Opterons?"

What are HE Opteron and EE Opterons?

Opteron HE ("highly efficient") processors are 55 watt versions (typical voltage 1.3 V) of the Opteron processor designed for environments where lower than standard power consumption (and consequently, lower heat production) is desirable. HE rated Opterons currently are only available in at 146, 246 and 846 2.0 Ghz speed. Opteron EE ("energy efficient") processors consume less power still at 30W, but are available only in sedate 1.4 Ghz 140, 240 and 840 versions (typical voltage 1.15 V). Standard Opterons consume between 80-90 watts (at 1.5 to 1.55 V typically).

What types of memory do Opterons require?

Opteron processors require registered ECC DDR RAM as opposed to common DDR RAM which can be used with AMD Athlon 64 systems. 940 pin Athlon FX processors also required registered ECC DDR RAM, since these processors are based on the 1xx series Opterons albeit with unlocked multipliers.

"Registered ECC" memory features additional registers and error correcting checksum functionality over standard DDR RAM. As the Opteron line of processors is primarily targeted towards business users, AMD has chosen to make this less error prone memory type a requirement.

Can I adjust the multiplier on an Opteron?

No method is of manipulating the multiplier used by an Opteron is currently known. If you only require a single processor system, and you need/want the ability to change multiplier, you should look at the 940 pin Athlon FX processor. The Athlon FX-51 (940 pin) processor operates at 2.2 GHz and is equivalent to an Opteron 148 with unlocked multipliers. The Athlon FX-53 (950 pin version) processor operates at 2.4 Ghz and is equivalent to an Opteron 150, again with unlocked multipliers. Expect to pay a price premium for the Athlon FX models over their Opteron counterparts. You cannot use more than one Athlon FX processor in the one motherboard (they will, like their 1xx Opteron brothers, not operate in dual or above processor configurations).

Opteron overclocking - can Opterons be overclocked?

Yes. Opteron motherboards generate a "base clock" (aka "reference clock") which will determine the speed at which the Opteron core will operate. This base clock figure multiplied by the Opterons multiplier will give you the speed at which the core runs. Increasing the base clock will proportionally increase the clock frequency of the Opteron core (eg, a 10% rise in base clock will result in 10% more core frequency). The base clock is not technically the equivalent of an Front Side Bus (FSB) frequency since the Opteron, with an on-die memory controller, does not have a FSB.

Opterons are relatively rarely overclocked with most enthusiast focus being directed to the cheaper range of Athlon 64 754 pin processors (which have less cache and only a single channel memory controller).

Reports have surfaced, however, of people taking 144 CEP revision Opterons to 2.2 Ghz using the Leadtek K8NW motherboard. As with any overclocking, you mileage may vary greatly. Consult any of the excellent AMD/overclocking forum websites which exist to stay current with the world of overclocking. Here is a start: www.amdzone.com/modules.php?op=modload&name=PNphpBB2&file=viewtopic&p=8232