question about Intel's new processor technology (SMT, etc.)

[Special K]

Could someone please clarify for me what exactly SMT is, and what the codewords stand for (Foster, Jackson, Prestonia, etc.)? I understand that it allows one processor to function as two in some respects (multi-threading), but does the CPU itself acutally have 2x the number of execution units as a normal P4, or what?

 

[AndyHui]

Foster is the XEON version of the Willamette Pentium 4.

Prestonia is the XEON version of the Northwood.

Jackson is Intel's code name for SMT technology on the Prestonia processor.

Have a look at this thread over in HT for more about SMT.

 

[Athlon4all]

Foster=Current Xeon. Much like Williamette
Prestonia= Northwood based Xeon. Has 512kb of L2 cache, and is the first Intel CPU with SMT enabled
Jackson= Code name for the SMT technology.

Now as for what does SMT do? Well, it allows a single processor to have multiple threads open at the same time. One of the main reasons for SMP is so you can have multiple threads open, but SMT does the same thing. Except that the threads will have to compete with the resources that are avialable. It does not have double the exceution units of the P4, but rather helps keep all the execution units in use. That's a weak explanation, but that is basically what it does.

 

[RaynorWolfcastle]

Is there any indication as to whether Intel will release large cache versions of prestonia ( a la P!!! Xeon)? Just curious since it seems database apps get a nice boost out of 2 MB of L2 cache.

-Ice

 

[AndyHui]

Now that the Northwood die is much smaller than the Willamette and produces a lot less heat, it should be viable for Intel to produce large cache versions of the Prestonia.