Dual Core & Dual Channel?

[ChipDeath]

I haven't bothered to <i>really</i> research the architecture of A64 chips, or I might have some idea myself about this, but still...

We know that Dual Channel memory does very little for the A64, as the extra bandwidth it provides is pretty much surplus to requirements, whereas the P4 is bandwidth-starved when not running Dual Channel so it benifits loads.

But what about the upcoming Dual Core chips? As they're twice the CPU, will dual channel finally have a considerable impact in performance for an AMD system?

Just curious..... Anyone know about this?

---
"Sex without love is an empty experience...
But as empty experiences go, it's one of the best" - Woody Allen

 

[phial]

well each core will have its own memory controller , wont they?



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[ChipDeath]

I guess so....

And they've been designed from the ground up to play nicely with each other with regard to resources and intercommunication (as I understand it)...

So I suspect it would provide a good boost, with the right applications.

Not sure about the timescales, but this <i>might</i> affect the PC I next build.....

---
"Sex without love is an empty experience...
But as empty experiences go, it's one of the best" - Woody Allen

 

[P4Man]

>well each core will have its own memory controller , wont
>they?

No. Dual core AMD chips will have only 2 memory controllers, like current 939 A64's and Opterons.

To answer the original question: its likely that P4 will suffer a bit more than A64 from going dual core for the reasons you mentioned (bandwith to the chip remains identical, or is halved per core).

Still, I don't expect major differences on this, because the issue is not so much bandwith as it is latency. 800 MHz not only doubles bandwith over 400 MHz, it also cuts latency in half, and that is what P4 is so sensitive about. And going dual core might increase average latency a bit, but no where near x2 AFAICY.

= The views stated herein are my personal views, and not necessarily the views of my wife. =

 

[jammydodger]

Dual channel mode does not half latency, if the clock speed was doubled it would but the clock speed of the RAM remains the same! Dual channel infact is bad for latency unless RAM chips are identical because the CPU has to wait for both chips to respond.

 

[P4Man]

I did not mean to say anything else (did I ?). Dual/single channel is not changed going dual core, but (theoritical max) bandwith per core is halved. Hence, similar latencies, less bandwith (per core), all in all, not big difference.

= The views stated herein are my personal views, and not necessarily the views of my wife. =<P ID="edit"><FONT SIZE=-1><EM>Edited by P4man on 02/09/05 06:48 PM.</EM></FONT></P>

 

[Crashman]

Not dual channel, but twice the frequency. Cas 4 at 800MHz is twice as quick as Cas 4 at 400MHz (because the cycles take half as long). This will have its most pronounced effect on DDR2 memory.

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