Parallel Processing, Part 2: RAM and HDD > Dual core S754 possible?

I have read the article and the performance difference between Dual and Single channel memory is... almost none?
So, would be possible to AMD develope a dual core Athlon 64 for ppl who want to keep their socket 754 systems (like me)? Or there's another problem such eletric current and etc?
Since AGP is still enough for a mid-range VGA and support DX10, a Dual Core CPU for this platform would be great, wouldn't?
Ok, it lacks from PCI-E and etc, but HT800 is very fast, fast enough to keep a dual core CPU, isn't?

Possible, yes. Viable no.
In the processor world, the most money is made in the high end chips. When AMD went to socket AM2 754/939 were forgotten, as the cost of R&D for the old platform was restrictive.
So no, there won't be a 754 dual core. Sorry.

AMD and it's IMC make it impossible to be dual channel and still s754, while Intel s478 has dual channel and even DDR2 capabilities, but still only a CoreDuo from the mobile market that is very inappropriate in performance/price from a completely new system is available for it. And I am not even sure of the CoreDuo thing as I haven't seen one with my eyes, just advertisements and unreliable sources. Worth a question though: Has anybody seen a s478 with 2 cores?

[quotemsg=1753574,6,58658]Intel's S478 is to AMD's S462 as Intel's LGA775 is to AMD's S754/939/940/AM2, from a technological point of view.[/quote]

Uh, perhaps a little more clarification:

Socket 462 ~ Socket 370/423/478
Dual Socket 462 ~ Dual Socket 370/Dual Socket 603
Socket 563 ~ Socket 370/478
Socket 754 (desktop) ~ Socket 478
Socket 754 (mobile) ~ Socket 479
Single Socket 940 ~ Socket 478/775
Dual/Quad/8 Socket 940 ~ Socket 603/604
Socket 939 ~ Socket 775
Socket AM2 ~ Socket 775
Dual Socket F ~ Dual socket 771
Quad/8 socket F ~ Quad+ socket 604/771 (Tigerton)
Socket S1 ~ Socket M/P
Socket AM2+ ~ Socket 775/upcoming socket 715
Socket 1207+ ~ Socket 771/Socket 1366 (Nehalem DP/MP socket, aka Socket B)

Note that they tested Intel CPUs with DDR2-800 rather than AMD CPUs with DDR-400. DDR2-800 is a little less than twice as fast as DDR-400 and the huge caches and prefetching of the Core 2 CPUs mitigate the reduced RAM bandwidth. Basically, the article was to give a memory management guide to 4 MB or 2x4 MB Core 2 owners. It didn't really see what would cause the performance to really drop off nor look at any AMD CPUs. Here's what they should have done:

1. Used DDR2-667, DDR2-533, and DDR2-400 RAM in addition to the DDR2-800 and seen how much bandwidth the CPUs really needed before their performance started to drop off precipitously.

2. Tested the 2 MB versions of the Core 2 Duo and the 1 MB Pentium Dual Cores alongside the 4 MB versions to judge the performance increase of the cache with reduced memory bandwidth, where it would arguably be more important. Either AT or THG did this with dual-channel DDR2-800 and the chips all clocked at 1.8 GHz. They found performance already drops 5-7% when going from 4 MB L2 -> 2 MB L2 and around 20% when going from 4 MB -> 1 MB. I'd like to see it with single-channel memory, especially DDR2-667, 533, and 400.

3. Tested AMD processors with varying cache sizes: the 2x256 KB L2 Windsor X2 3600+, a 2x512 KB chip, and a 2x1 MB L2 Windsor. And test them with DDR2-667, 533, and 400 as well as 800.

That would give a good clue as to how RAM bandwidth and cache size affect performance. Simply yanking a stick out of a dual-channel setup on one kind of CPU is informative only for that speed of RAM and CPU they were using.

That's not possible to do. You would need to make an MCM and that would require giving each die its own access to the memory as well as having an HT link between the two dies, as well as having some way to control that. You'd need a socket with dual-channel RAM connections (one for each die's IMC) and also with the pins and a chipset that handles the cache-coherent HT needed to link the two dies. You could probably do it with a socket 940 or 1207 Opteron board as the pins and chipsets support the ccHT links and there are two memory channels wired to the socket. Socket 754 lacks the extra pins for the ccHT links and the chipsets wouldn't know what to do with it anyway. So you'd need a monolithic die with all core-core and core-IMC traffic handled on-die. Probably the easiest thing for AMD to do if they wanted to make a dual-core 754 chip would be to plop a Manchester/Toledo X2 die on the 754 package and only wire up one channel to the IMC.

A lack of PCIe is pretty critical in today's day and age. AGP is basically dead and PCI is heading that way. With parts being the prices they are today, you would do well to get a new board, CPU, and RAM rather than try to upgrade a 754/AGP system any further.