Socket 940 and Socket 939

[ShinRa]

Ok ive been researching socket 939 lately for the amd athlon 64, and trying to compare it to the 940. And I still have no idea what the hell the difference is because its not in english, its in nerd terms. Can someone PLEASE for the love of god explain the difference between these two!? And if it's even worth waiting for?!

 

[Asus]

The difference is 2 things.
1) the pin count
2) a requirement....

The requirement is to use Registered Memory.
The memory a normal desktop system has is unbuffered memory.
Memory is either Unbuffered or Registered(buffered).

In order to know where data is located in memory it has to be registered, marked or remembered. How every you want to think of it.
In normal desktop PCs, the memory controller registers the data so it knows where it is located.
Think of this as the front desk at a hotel/motel.
In workstations and servers, the memory registers the data that goes in it's own memory. It allows for more memory to be added without a performance hit.

The memory controller or front desk has limits has to how much data it can effectively register.
By switching to each memory stick doing the registering on it's own you get rid of that limit and so you can add beyond 4 banks of memory with out a performance hit. Banks != sticks/slots. You used to have to know about banks back in the day when memory came in 4mb/8mb sticks. You had to have 1 full bank of memory which ment you had to have 2 or 4 sticks. lol
A stick today is made up of 2 or more banks usually. The smaller sizes are 1 bank I guess.

Read Me

Does that help?

 

[ShinRa]

thx asus. so the socket 939 will use unregistered (unbuffered) memory?

 

[[Matt]]

If you have a Socket 940 just cot off one of the corner pins.... instant socket 939 CPU!!!! :E

(dont attempt this im just bieng stupid)

 

[Asus]

thx asus. so the socket 939 will use unregistered (unbuffered) memory?

Correct.
Just like you are using now.

 

[ShinRa]

And..in turn that is better....correct?

 

[Asus]

Are you every going to add 3 512MB sticks of RAM in your PC?
If yes, Socket 940 would be best.

If no, Socket 939 would be best.

Unless you want the benefits of ECC memory (Error Checking and Correction), then Socket 940 is the way to go again.

hehe
Confused?

 

[Daegon]

Ok, I'M confused, are you saying that 940 can't support ECC?

regisetered and ECC are mutually exclusive?

 

[Asus]

You can buy ECC Registered RAM for Socket 940.
Or
Non-ECC Registered RAM.
ECC is an option for Socket 940.

You cannot use ECC or Registered RAM on Socket 939.
It's normal Non-ECC unbuffered RAM.
so...

Socket 939 - I want the lowest possible memory latency. I don't care about ECC. I will never add 3 sticks of 512MB RAM (>4 Banks) or I don't care about the performance hit if I did.

Socket 940 - I don't mind a slight rise in latency for memory for the other benefits. I would like the option to use ECC memory. I would like the option to add 3 sticks of 512MB or more (>4 banks) with out any performance hit if I did.

 

[ShinRa]

But do you think socket 939 will be around by the end of june? cuz thats when i wanna start ordering my stuff. (basically when the xt comes out

 

[Asus]

AMD Socket 939 CPUs.
AMD Socket 939 Asus board and here.

Expect many things to be released or displayed at Computex 2004 (June 1-5)

 

[ShinRa]

So the AMD 3800 is faster than the FX-53?

 

[Asus]

So the AMD 3800 is faster than the FX-53?

No.
Athlon 64 FX-53 runs at 2.4GHz, has 1MB of L2 Cache.
Athlon 64 3800+ runs at 2.4GHz, has 512KB of L2 Cache.

Both have dual channel memory.
If they release a Socket 939 FX-53 then that will be slightly quicker than the Socket 940 version.

3800+ vs 3500+ vs 3400+ vs 3200+ vs P43.4 vs P43.2 (Northwood)
Babelfish French to English
Preview
Not the best of benchmark choices.

 

[ShinRa]

So I'm better off getting the FX-53 unless they release a socket 939 FX-53 which probably wont be in june right?

edit - thx asus sorry im such a pain in the ass

 

[Asus]

So I'm better off getting the FX-53 unless they release a socket 939 FX-53 which probably wont be in june right?

edit - thx asus sorry im such a pain in the ass

Basicly.

 

[ShinRa]

Ok so I'm goin with the FX-53, and now I'm getting registered ram...which i think from what you say is slower...so since i have to go with slower ram, whats the absoulte fastest/best ram i could get for this processor? im going with the SK8V asus mobo if that helps any.

 

[Asus]

Ok so I'm goin with the FX-53, and now I'm getting registered ram...which i think from what you say is slower...so since i have to go with slower ram, whats the absoulte fastest/best ram i could get for this processor? im going with the SK8V asus mobo if that helps any.

Memory with 2-3-3-6 timings are fine.
Probably what you will expect when looking at that type of memory.

Timings don't matter that much with an A64 system though. They have a really low latency memory controller so you can't really be that much quicker.

Just avoid the CL3 and CL2.5 timings.

You might as well get memory that is Registered and ECC.

OCZ
Corsair

 

[ShinRa]

I found this:

Corsair XMS Extreme Memory Speed Series, (Twin Pack) 184 Pin 1GB(512MBx2) Registered DDR PC-3200 w/ Platinum-Silver Heat Spreader - Retail

Specifications:
Manufacturer: Corsair
Speed: DDR400(PC3200)
Type: 184 Pin DDR SDRAM
Error Checking: Non-ECC
Registered/Unbuffered: Registered
Cas Latency: 2-3-3-6
Support Voltage: 2.6V
Bandwidth: 3.2GB/s
Organization: two 64M x 64 -Bit


That good?
btw asus thx for everything. i wouldnt be able to build this super computer if it wasnt for you. im going to put that asus sticker on my case as a tribue to you!

 

[Asus]

I would proabably get the ECC memory since the Registered part is what adds the latency. You already got the latency so why not add in ECC?
ECC checks memory and corrects errors so they don't unexpectedly pop up in programs and crash them. hehe

Not to mention the ECC is cheaper and has slightly better timings.
With ECC
Without ECC

 

[ShinRa]

Does this latency make me slower than other processors or computers?

 

[ShinRa]

And I found this:
Corsair XMS Extreme Memory Speed Platinum Series, Low Latency (Twin Pack) 184 Pin 1GB(512MBx2) ECC Registered DDR PC-3200 - Retail

Manufacturer: Corsair
Speed: DDR400(PC3200)
Type: 184 Pin DDR SDRAM
Error Checking: ECC
Registered/Unbuffered: Registered
Cas Latency: 2-3-2-6
Support Voltage: 2.6V
Bandwidth: 3.2GB/s
Organization: two 64M x 72 -Bit
Special Features: Plug-n-Frag Auto-Configuration

 

[ShinRa]

Sorry asus u must wanna kill me but i also found this: which one of these two?

Corsair XMS Extreme Memory Speed Series, 184 Pin 1GB ECC Registered DDR PC-3200

Manufacturer: CORSAIR
Speed: DDR400(PC3200)
Type: 184 Pin DDR SDRAM
Error Checking: ECC
Registered/Unbuffered: Registered
Cas Latency: 3-3-3-8
Support Voltage: 2.6V
Bandwidth: 3.2GB/s
Organization: 128M x 72-Bit
Special Features: Plug-n-Frag Auto-Configuration
Warranty: Lifetime
100% tested at DDR400 (200 MHz) in Athlon 64 FX motherboards

 

[Asus]

Here - Link

Notice the bandwidth is the highest there is! A standard A64 (socket 754) is only single channel memory which is why they are down there.

Now notice the Latency test at the bottom of the page.
A64 FX-53 is just slightly above the A64's. That is because of the Registered Memory.
Noticably ahead of the P4 and AXP still.

FX CPUs will bring the latency down by...3 points. Is that worth waiting or paying more for?

 

[ShinRa]

And...oh christ 4 posts im so dead.....dont kill me just yet mods....

asus i just looked @ that ocz ram. ill take that into account if you think thats best. im the kind of noob who thinks if it isnt the most expensive part, it isnt the best. cuz the ocz is 300 opposed to corairs xms being 350-400. idk asus, your call, you tell me - if u were getting the fx-53 with the sk8v mobo what memory would u get?

 

[monofurioso]

I'm looking to build a system simlar to the one guinny is trying to piece together. Everything I've read tells me that the Opteron 150 is identical to the FX-53. It's also currently $180 bucks cheaper and will run on the SK8V.

See any reason not to go with the Opteron for a great Doom3/HL2 rig?