PCI Express Socket 939 Mobos Anytime Soon?

So what's registered memory?

Isn't DDR dual channel? How is DDR2 different than DDR? And can't you run with DDR sticks in a DDR2 board?

I'm confused. Darn it I just want to play Far Cry, BF Vietnam, Joint Ops, and Half Life 2 when it comes out.
 
DDR2 memory runs at higher clock speeds, but with higher latency. It is a different socket, and the two are not compatible.

The Athlon64 platform isn't likely to use DDR2 at any time in the foreseeable future. It has no reason for trading low latencies for higher clock speeds. Key element of A64 is the very low latency memory subsystem. It isn't in need of a higher memory clock speeds.

Analogy: Think of latencies as acceleration and clock speed of top speed. You can always use fast acceleration, but only top speed on few occasions. You could say that with DDR2 (and GDDR3) they are using a "gear", to give even better top speed, but degrading acceleration. The memory on graphics cards are tuned even more for top speed.
A comparison of the different kinds of memory:

DDR1:
PC3200: CAS Latency 2
PC4000: CAS Latency 2.5

DDR2:
PC3200: CAS Latency 3
PC4000: CAS Latency 4
PC5300: CAS Latency 4

GDDR3:
"PC8000" - "PC11200": CAS Latency 5 - 9

As frequency scales, timings get more loose. That's no problem for video cards, as they have huge amounts of data to process. With normal processors running normal tasks, it is much better to have low latencies, as they very rarely have the need for large amounts of data.
An example of that is the performance difference between socket 939 and socket 754. In a lot of cases, the difference is very small. Though the addition of dual-channel effectively eliminated the need for higher clocked memory.

I'm sure that we will see DDR1 PC4000 with CAS latency 2 sooner or later.
 
Eric, The A64 has the memory controller on board the cpu. Thus, the 939 cpus have dual channel capability on board where as the 754(?) do not. It doesnt matter if the mobo has support for RDRAM, the CPU will only utilize single channel DDR in the 754. Now, what can happen is that you can use either RAM in each system, just 754 boards will only be able to run DDR in single channel mode, where as the 939 boards can run it in dual channel if you have it configured right(ie ram installed in pairs in the right banks)


So, if in the future anybody wants to run DDRII and the 939 platform supports it, it will require a NEW 939 cpu with a DDRII controller. This is assuming of course AMD goes to the DDRII platform, and when the do, stay with the same socket. I doubt that they will however.

Lastly, DDRII and DDR are different types of ram in the sense that they are not compatible.
 
In that, what do 'S' and 'MP' mean? Am I reading correctly that there will be dual 16x PCIe on 939 in August, or at least Q3??
 
I was trying to figure out those as well....


I look foward to the reviews even if I'll still be running AGP.

My dream is still have an AGP slot with PCI-E for raid etc
 
Esben said:
DDR2 memory runs at higher clock speeds, but with higher latency. It is a different socket, and the two are not compatible.

The Athlon64 platform isn't likely to use DDR2 at any time in the foreseeable future. It has no reason for trading low latencies for higher clock speeds. Key element of A64 is the very low latency memory subsystem. It isn't in need of a higher memory clock speeds.

Analogy: Think of latencies as acceleration and clock speed of top speed. You can always use fast acceleration, but only top speed on few occasions. You could say that with DDR2 (and GDDR3) they are using a "gear", to give even better top speed, but degrading acceleration. The memory on graphics cards are tuned even more for top speed.
A comparison of the different kinds of memory:

DDR1:
PC3200: CAS Latency 2
PC4000: CAS Latency 2.5

DDR2:
PC3200: CAS Latency 3
PC4000: CAS Latency 4
PC5300: CAS Latency 4

GDDR3:
"PC8000" - "PC11200": CAS Latency 5 - 9

As frequency scales, timings get more loose. That's no problem for video cards, as they have huge amounts of data to process. With normal processors running normal tasks, it is much better to have low latencies, as they very rarely have the need for large amounts of data.
An example of that is the performance difference between socket 939 and socket 754. In a lot of cases, the difference is very small. Though the addition of dual-channel effectively eliminated the need for higher clocked memory.

I'm sure that we will see DDR1 PC4000 with CAS latency 2 sooner or later.
Click to expand...


Anand posts that single and dual channel can be a 8 to 10% performance difference, which is not small me thinks.
 
So according to Anand it looks like what I've been waiting for will be the K8T890 Pro chipset based mobos. Seems like they should be at retail in Q3 of this year too, not Q4 like expected. I hope this turns out because it looks like HL2 is going to be available sooner than expected too what with preloading beginning this week supposedly.

I do have a couple questions if anyone can answer them though:

1) What socket 939 processors is AMD going to be introducing next and in what timeframe? I'd be very interested in a lower clocked 939 A64, something like a A64 3000 but socket 939 instead of 754.

2) Has ATI given any timeframe for their next refresh of vid cards based on the R4xx core? I'm still not sure if I want to go with an X800 something, or a 6800 something, or possibly two 6600 somethingS running in SLI. It'll be interesting to see how all the above mentioned cards REALLY perform in-game when HL2 comes out. For as much as the GeForce cards have been dominating Doom 3, I'm anxious to see how they perform in HL2 since Valve keeps asserting that ATI is the way to go with their game.
 
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