Interesting question, got me wondering if my Core 2 Duo cpu would look the same. Haven't had the chance to check it yet, but I did some reading and found that it seems neither the Pentium D 805 or my Core 2 Duo 6400 have hyperthread technology although they're both dual-cores.
I haven't finished studying the Intel® 64 and IA-32 Architecture manuals yet, but suspect the software developers reference manual hints at the explanation: "The Intel Pentium D processor also features multi-core technology. This processor provides hardware multi-threading support with two processor cores but does not offer Hyper-Threading Technology. This means that the Intel Pentium D processor provides two logical processors in a physical package, with each logical processor owning the complete execution resources of a processor core." At a SWAG the HT bit is set because there is more than one logical processor, in the case of the D 805 (and my Core2Duo) they are each a physical core but for some reason are logically equivalent to a single core with HTT, at least enough to justify setting the flag bit that way. It could be that the flag is set in bios or os code that verifies more than one logical processor without distingushing physical cores from HTT logic. ref p.52 of the Intel manual: <http://www.intel.com/design/processor/manuals/253665.pdf> also, the table on page 18 of a good review of the D 805 on Tom's Hardware shows the D 805 has no HT implementation, but comments on the equivalency of dual-core. Find it at: <http://www.tomshardware.com/2006/05/10/dual_41_ghz_cores/page18.html> That article also says the D 805 looks like a great overclocker, the biggest reason I prefer my Core2Duo is power consumption, but with the 805 in hand I might look for a good overclocking mobo to take full advantage of it, if that's your interest. Hope this is helpful! -Bruce ---- Original message ---- >Date: Wed, 25 Apr 2007 10:14:05 -0400 >From: "Bob King" <[EMAIL PROTECTED]> >Subject: Pentium 805D has an interesting surprise >To: "Greater NH Linux User Group" <gnhlug-discuss@mail.gnhlug.org> > > During the Xen discussion at MerriLUG, it was > mentioned that the Xen implementation on FC6 > required PAE on the cpu. I knew that my two Linux > boxen at home did not support VT<X>, so I checked > the processors for the PAE flag. > > My Xeon system had PAE and also supported > hyperthreading, which was hardly a surprise. > > However, when I checked my Pentium D 805 system, it > showed PAE and HT as well. I new the 805 was a > dual-core, but was surprised to see the HT flag. I > cannot find anything on Intel's websites that talk > about HT support, nor does the bios for that systems > motherboard support it for me to be able to test it. > My initial attempts at googling for info have been > inconclusive. Most references to the cpu flags are > discussing other flags, not the 'ht' flag which is > shown but not explicitly discussed. > > I was wondering if anyone had heard anything about > this? If the cpu really supports hyperthreading then > I might want to invest in a new mobo for that box. >________________>_______________________________________________ >gnhlug-discuss mailing list >gnhlug-discuss@mail.gnhlug.org >http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
