I understand the basics about dual cpu and dual core, what I do not understand is when it is best to purchase one over the other. What are the pros and cons of both. Then add on top of that buying dual opterons. At what point does one know when that would be more beneficial. There has to be more guidelines than trial and error to determining this.

In a dual CPU system does the second CPU kick in automatically when the first gets bogged down or does the application have to be written for it? Is that the beauty of dual core only?

A lot is said about bandwidth nowdays. Does this apply to opterons also? Do they have a larger bandwidth therefore can push more data in a given timeframe?

Staying in the AMD family at what point would a single core A64 4600+ or 5000+ chip equal a single core Opteron.

LET ME EXPLAIN MY POSITION
I have a 2 year old machine that is running 6 monitors. I use it for trading securities/currency/etc. This is only for 2D no 3D involved.

CPU P4 2.8 GHZ
Video cards Quadro 900xgl-128MB(AGP), Quadro NVS 400-64MB(4 port pci card)
HDD - wd80 gig

Each monitor has a financial chart and shows the result of 10 real time trading systems analysis. This bank of 6 screens gets switched when I want to view a different security or currency. Everything from the old is taken down and everything from the new is put up. The problem is, it takes 45 seconds for the change over I need it/want it to take about five.

I have made some temporary changes.
Asus A8N-SLI Mb running A64 single core 3000+
2-2 port PCI-Express cards-(I did some benchmarks see below)
scsi - Seagate Cheetah 18gig/Adaptec 29160 - U160 combo in a pci slot (32bit)

My change over time has been reduced to no more than 10 seconds. I am considering buying a new rig to replace this temporary setup. Thank goodness the Core 2 Duos are here to give me more options. Here is the dilemma. What board? What type of CPU? and What CPU?

I will be getting an ATI FireMv, and Matrox cards designed to accelerate 2D work. I now have an Adaptec 2200S/64 RAID controller. This is a 64bit card U320 controller w/ 4 -5 18 gig U320 Atlas drives.


For motherboards I am looking at the
TYAN (K8WE-S2895A2NRF) up to 2 single or dual core 200 series Opteron CPU's
http://www.tyan.com/products/html/thunderk8we.html Dual Opteron CPU, and the
ASUS (P5WDG2-WS)
http://usa.asus.com/products4.aspx [...] odelmenu=1 -Core 2 Duo. Both are very nice with Pci-Express, Pci-X 133Mhz and Pci v2.3 slots.

In looking at the Core2Duos the most I would want to spend would be what would put me in the E6600/E6700 ballpark. (the Tyan board must have 2 CPU for both PCI-E slots to work.) What I need to get in dual Opterons to have at least the processing power of a Core2Duo E6700. The software I am currently using is not written to take advantade of multiple cpu's but may be in the future or I may change software in the future. This machine is dedicated to this task alone.

I want the best bang price performance for now and a path to upgradability in the future.

My biggest concern is how the CPU's compare. I did a total cost of ownership analysis on both motherboards and everything else is a virtual wash.

Thanks for your help. If you have any other questions feel free to ask. Also if you have found any documents explaining and comparing these CPU please send me the links.


Single core opterons seem to be cheap on Ebay. What minimum 200 series single core and dual core would I need.

Depends if you are willing to fork out $4-5K for workstation which is common for Opteron/Woodcrest systems due to more expensive RAM, components, etc. At work, we have Tri-LCD panel monitors (forgot the brand) that is normally used in your line of work (securities). These panels are controlled by dual video cards (the expensive part and possible bottleneck) and cost under $1500CDN (cheap). I've seen the 6 LCD panel models that are sub $2500CDN (affordable).

If your apps are multi-threaded (ask - but you mentioned not supporting multi-CPUs which is another of saying not mulithreaded) and are CPU bound (check Task Manager) then dual Opteron will be the way to go. Also workstation/server motherboards have WAY more bandwidth than consumer garbage so if your applications are network sensitive and you already are on gigabit then mobos with PCI-X (or multiple PCIe slots - a sign the mobo is meant for large bandwith processing) are for you.

When you say that "workstation and server MB's have more bandwidth" What does that actually mean?

Opterons offer:

2 x the memory bandwidth in 2way SMP = 2 x 3200 = 6400 in Single Channel

4 x the memory bandwidth in 4way SMP = 4 x 3200 = 12800 in Single Channel

8 x the memory bandwidth in 4way SMP = 8 x 3200 = 25600 in Single Channel


The Tyan S2895A2NRF offers 2 real 16X PCI-E slots with 32 PCI-E lanes which is double the PCI-E bandwidth most other boards offer. It has more PCI-E lanes for the other PCI-E slots as well and it offers 2 independent PCI-X buses one running @ 64 x 133 MHz = 8.512Gbps and other running at 64x100 MHz = 6.400Gbps.

So you have a LOT more bandwidth.

Intel systems are still FSB limited even the new woodcrest suffers from that.

On Intel P4 Xeons:

2 CPUs = 1/2 the memory bandwidth

4 CPUs = 1/4 the memory bandwidth

8 CPUs = 1/8 the memory bandwidth

With Dual Cores it gets worse:

4 Cores = 1/4 the memory bandwidth

8 Cores = 1/8 the memory bandwidth

16 Cores = 1/16 the memory bandwidth


Keep in mind AMD's new socket F is due out soon!!


GL!

That is such a cool diagram. Looks like a large armed force ready for battle.

Looking back at the original post....

Dual core / Dual cingle core CPU makes little difference in most cases. Dual Core theoretically means less latency between the cores (especially on AMD cpus with the crossbar and Core 2 Duo with the shared L2 cache) but this has shown to not always be implimented as well as it should.

In the case of AMD cpus, dual single core CPUs means twice the memory bandwidth and more downstream HT bandwidth to the rest of the system. Intel CPUs (even Core 2 Duo and Woodcrest) share the FSB and memory bandwidth no matter how many cpus you have. Of course dual CPU boards are more expensive as are 200 and 800 series Opterons and Xeons that are needed for dual CPU setups.

You say 'does the second core kick in when the first is busy', well not quite.

One 'thread' or normal application can only run on one processor, be it one core of a dual core CPU or one CPU of a dual cpu pair. That is to say that that thread can max out the one core and be thirsty for more, but cant touch the second core.

Of course background processes can access the other core leaving the first CPU entirely for the first application.

This is the case regardless of the method you use to have multiple processors, unless the application in question is designed to split itself into multiple parts. You need to find out if your share program is 'multithreaded' as in it can run on multiple processors. If not then going the multiple CPU route wont gain you much.

You also seem to be under the impression that the A64 4600+ and 5000+ are single core CPUs, they are NOT, they are both Dual core.

Assuming you used a Single core Opteron of the same speed and cache size as the equivalent A64, you would see identical performance.

The same with matched Dual core A64s and Opterons.

They are the same CPU, the Opterons are just ones marketed at servers and workstations. Most of the 'proper' opterons use Socket 940, and need different motherboards, they are availible in 100 series (single CPU only) 200 series (1-2 CPUs, up to 4 cores with 2 dual core CPUs) and 800 series (1-8 CPUs, up to 16 cores with 8 dual core CPUs)

There are also Socket 939 Opterons, these are exactly the same as S939 A64s.

There are some arguments that the Opterons may be 'binned' CPUs, as in they are the best quality ones, but this isnt really relevent if you are not overclocking.

There is little point, imho, going for two single core Opterons. You could save yourself a fortune on the motherboard etc by just useing a single Dual Core A64 on a mainstream motherboard, and the performance difference would be moot.

If you want to go for two dual core opterons, then maybe