Intel Yamhill... 64 bit ?

[VJ]

Hello,

I'm noticing on various sites there are rumours of Intel also having a 64 bit processor... Speculations is that it will be in PIV and Xeon (no longer only Itanium). Some even speculate that the circuitry is present, but inactive (a bit like hyperthreading just before it was launched).

Does anybody have more info on this ?

Any ideas on backward compatibility ?


Jörg

[TransformX]

Wombat ?

[Wombat]

Having x86-64 designed into Intel processors, well, wouldn't surprise me.

[The PIT]

Don't worry I'm sure Intel won't let AMD have it all there own way. They'll keep an eye on the sales. Intel doesn't seem quite so driven my Marketing people these days.

[Ribbit]

Prescott does have a lot more transistors than Northwood...

[The PIT]

Originally posted by Ribbit
Prescott does have a lot more transistors than Northwood...

Isn't that mainly due to the larger cache ???

[Chrono_Wanderer]

yea...

besides, the transistor gain from Athlon XP to Athlon 64 wasn't too much actually, I read its only around 5%. There are ~100 transistors on the A64, but I think it is transistors for the 1MB L2 Cache... (and the integrated memory controller)

I don't see how a socket 478 CPU can be a 64bit CPU... if they plan to ever enable it they'd put in more pins in the first place. Though I may be wrong...

Oh ya, is there a way to force HT on the first northwoods? (like mine)

[Tjalfe]

they would only need more pins for address lines for more than 4GB of ram, the memory interface is already 64 bit, so I guess they could do a 64bit version with a 4GB limit in the current sockets

[Topha]

In this article, they talk about how there are about 40 million transistors too much in the prescott. it has 125 compared to the 55 in the northwood core, and only ~26 million can be due to the extra cache of the prescott. The other new features should take up too much space either, so those 40 million transitors are either 64 bit or dual core or both or something entirely new.

The article is in german, so you may need a translator

[VJ]

http://news.com.com/2100-1006_3-5150336.html?tag=nefd_top

Intel plans to demonstrate a 64-bit revamp of its Xeon and Pentium processors in mid-February--an endorsement of a major rival's strategy and a troubling development for Intel's Itanium chip.

The demo, which follows the AMD64 approach of Intel foe Advanced Micro Devices, is expected at the Intel developer conference, Feb. 17 through 19 in San Francisco, according to sources familiar with the plan. Intel had code-named the technology Yamhill but now calls it CT, sources said.

Judging by the fact they still use the terms Pentium4 and Xeon, I'd guess it would have to be a same socket...

Originally posted by tjalfe
they would only need more pins for address lines for more than 4GB of ram, the memory interface is already 64 bit, so I guess they could do a 64bit version with a 4GB limit in the current sockets

Slightly off topic (and this in my own thread ):
I know about the 4 GB limitations. Now, my mainboard supports up to 12 GB RAM:

http://www.supermicro.nl/PRODUCT/MotherBoards/E7505/X5DA8.htm

How is that additional memory used (not that I have it)?


Jörg

[isochar]

Xeon's have 36-bit addressing, meaning they can support up to 64gb of RAM.

[VJ]

Ha, I see...
(I didn't really give it much thought, I just needed (wanted?) the CPU power...)

Jörg

[az]

Though they must do this through some kind of dirty emulation.. it's slow, and has some other downsides. I believe there was a piece on ace's about that in one of their 64 bit articles.

AZ

[az]

Ace's is down at the moment, though.

AZ

[Ribbit]

Intel CPUs since the PPro have PAE (Page Addressing Extensions), which lets them address up to 64GB physical memory. However, your programs are still limited to a 4GB virtual address space each - what PAE lets you do is, say, have several programs in memory which are each using 2GB. There's probably a mechanism to let a program use more than 4GB, but it will be through an Evil EMS-type paging hack.

Athlons have PAE too, but I don't think they make the extra address lines available on the socket - it's just for P6 compatibility.