I'm wondering if someone can outline the difference between these two CPU lines for me? I checked AMD's site, but just found a marketing difference that classified the Athlon as a "home" CPU and Opteron as a "work" CPU... not too helpful. I've heard it tossed around that Optys are better for overclocking. Is this the case, and if so why?
The Opteron is a Server CPU so it is built to be very stable and reliable. It also requires an Opteron compatible motherboard and expensive Registered ECC RAM.
The Athlon 64 939 CPUs are awesome do not require Registered ECC and are frequently faster although sometimes have less L2 cache (usually half - but not always).
Opteron server boards typically have high-end server components like PCI-X slots, sometimes have 2 or more independent PCI buses for twice the performance and can support a lot more RAM than normal motherboards.
A typical motherboard supports up to 4GB RAM max if you are lucky, a nice Opteron board usually supports 16GB RAM or MORE.
Some Opteron boards also have enterprise level features and onboard SCSI sometimes with RAID or a special zero-channel RAID slot.
Also consumer boards have 1 939 CPU socket whereas Opteron boards have 2, 4, 8 or more CPU sockets for Dual, Quad, 8way and N-way SMP (symmetric multiprocessing).
I have actually built several Dual Opteron servers and they are very nice although they can be quite expensive.
Well perhaps your education on opterons and smp on the desktop is a bit dated. The Opteron 1 series is for workstations in single CPU environments. In fact, the best gaming platform out right now for overclockers is the Opteron 1 series for 939, yes 939. They do NOT require ECC or Registered ram. Since they are an opteron they are cooler and more stable. People are getting the 165 which is a dual core 1.8Ghz with 1MB L2 per core. They run either 1.3 or 1.35 (cant remember which) on the vcore and will often clock to around 2.4ghz on OEM coolers at that voltage. Then bump em up to about 1.5V and get usually 2.8ish with a decent cooler Think of it as a dual FX59 (if it was made now) for $345. There is a single core 146 I think that clocks often to 3+ghz and its only about $240. Go check out some forums. Anandtech's boards have alot as do others. In fact I think there was an article about it on their site recently.
Its worth looking into. The DFI expert mobo is the best there is for OCing but even some cheap ASRock boards can do a good bang for the buck work. Imagine an Aspire case with the ASRock NF 4100 based system with a $240 single core and a 6800 GS with 22.214.171.124 Patriot. What, $800ish and incredible performance?
Aye, I have heard of this new opteron but have not had any first-hand experience with it so I left it out of my post completely.
I was only referring to 2, 4, 8 and n-Way SMP in my post.
Models 2xx, 4xx, 8xx, etc
The other really cool thing about the Opterons is that they have dedicated Hypertransport buses just to communicate with each other as well as having the integrated memory controller leading to their own dedicated RAM so if you buy enough RAM each opteron in your system can have its own 2, 4, 8 or more GB or RAM all to itself. This RAM is sharable via the CPU to CPU Hypertransport links.
This is really wicked, back in the day this was unheard of -- CPUs in SMP machines had to jump through hoops to talk to each other.
The Opterons also have the bandwidth to offer really FAST access to PCI, PCI-X, PCI-Express and sometimes AGP interfaces on the motherboard and as I mentioned previously some Opteron motherboards even have 2 or more PCI-X buses for TWICE the bandwidth. Tyan for example makes the S2882 board which has 2 x 64bit PCI-X buses each capable of up to 133MHz operation. This is NOT the same as having 2 x 64bit PCI-X slots each bus can work independently has the full bandwidth of a PCI-X bus running at 64bit x 133MHz.
Yes, all A64 based stuff is similar. The hypertransports are used to link diffrent CPUs as well as different cores. They each have an individual L2 cache. That'll change on future revisoins (M2 maybe?)
The new Xeon thats just releasing is similar, with UNSHARED memory bandwidth so the performance difference should be narrowing. We'll know really soon.
There are also desktop boards with dual TRUE x16 PCIe, only the newest Nforce4's can do that though.