Editing Tejas and Jayhawk (section)

==Design and microarchitecture==
Tejas and Jayhawk were to make several improvements on the Pentium 4's [[NetBurst|NetBurst microarchitecture]]. Tejas was originally to be built on a [[90 nm]] process, later moving to a [[65 nm]] process. The 90 nm version of the processor was reported to have 1 MB L2 [[CPU cache|cache]], while the 65&nbsp;nm chip would increase the cache to 2 MB. There was also to be a [[dual core]] version of Tejas called ''Cedarmill'' (or ''Cedar Mill'' depending on the source). This ''Cedarmill'' should not be confused with the 65 nm Cedar Mill-based Pentium 4, which appears to be what the codename was recycled for.
[[File:Intel Jayhawk Thermal Sample Chip.jpg|thumb|A thermal sample of an Intel Jayhawk CPU, with the [[Sspec]] QBGC]]
The [[trace cache]] capacity would likely have been increased, and the number of pipeline stages was increased to between 40 and 50 stages.<ref name="tweakers">[http://tweakers.net/reviews/740/chip-magicians-at-work-patching-at-45nm.html Chip magicians at work: patching at 45nm]</ref> There would have been an improved version of [[Hyper-Threading]], as well as a new version of [[Streaming SIMD Extensions|SSE]], which was later backported to the Intel Core 2 series and named [[SSSE3]]. Tejas was slated to operate at frequencies of 7 [[GHz]]<ref name="dat inquiry">{{cite web|last=Dutton|first=Paul|title=Pentium V will launch with 64-bit Windows Elements|url=http://www.theinquirer.net/inquirer/news/1035334/pentium-v-will-launch-with--64-bit-windows-elements|archive-url=https://web.archive.org/web/20090511145152/http://www.theinquirer.net/inquirer/news/1035334/pentium-v-will-launch-with--64-bit-windows-elements|url-status=unfit|archive-date=May 11, 2009|publisher=The Inquirer|access-date=31 March 2013}}</ref> or higher. However, it's likely that Tejas wouldn't have had linear performance scaling, as it would on average have executed fewer instructions per clock cycle due to more pipeline bubbles from branch mispredicts and data cache misses. Also, it would have run hotter as well with a [[Thermal design power|TDP]] much higher than the Prescott core of Pentium 4. The CPU was cancelled late in its development after it had reached its [[tapeout]] phase.<ref name="tweakers" />

Initial claims reported early samples of single core 90 nm Tejas running at 2.8 GHz and rated for 150 W TDP on the [[LGA 775]] socket,<ref name="anandtech">{{Cite news|url=http://www.anandtech.com/show/1217|title=Covert Ops in Taiwan - Intel Tejas & Socket 775 Unveiled|last=Shimpi|first=Anand Lal|access-date=2016-12-01}}</ref> a notable increase over single core 90 nm Prescott (Pentium 4 521, 2.8 GHz, 84 W TDP)<ref>{{Cite news|url=http://ark.intel.com/products/27461/Intel-Pentium-4-Processor-521-supporting-HT-Technology-1M-Cache-2_80-GHz-800-MHz-FSB|title=Intel® Pentium® 4 Processor 521 supporting HT Technology (1M Cache, 2.80 GHz, 800 MHz FSB) Specifications|newspaper=Intel® ARK (Product Specs)|access-date=2016-12-01}}</ref> and higher than 90&nbsp;nm dual core Smithfield (Pentium D 820, 2.8 GHz, 95 W TDP).<ref>{{Cite news|url=http://ark.intel.com/products/27512/Intel-Pentium-D-Processor-820-2M-Cache-2_80-GHz-800-MHz-FSB|title=Intel® Pentium® D Processor 820 (2M Cache, 2.80 GHz, 800 MHz FSB) Specifications|newspaper=Intel® ARK (Product Specs)|access-date=2016-12-01}}</ref> In contrast, 65 nm dual core Core 2 Duo processors had a maximum of 65 W TDP (E6850, 3.00&nbsp;GHz)<ref>{{Cite news|url=http://ark.intel.com/products/30785/Intel-Core2-Duo-Processor-E6850-4M-Cache-3_00-GHz-1333-MHz-FSB|title=Intel® Core™2 Duo Processor E6850 (4M Cache, 3.00 GHz, 1333 MHz FSB) Specifications|newspaper=Intel® ARK (Product Specs)|access-date=2016-12-01}}</ref> while being much more efficient with markedly higher performance per clock.

However, the existence of [[engineering sample]]s have been challenged and no source indicates that tape-out of Tejas ever existed - the sample shown in the [[AnandTech]] article <ref name="anandtech" /> being a Prescott B0 ES.<ref>{{Cite web|url=https://twitter.com/d0cTB/status/1039585378792099842|author=Samuel Demeulemeester|date=2018-09-11|access-date=2018-09-12|title=J'ai enfin résolu un mystère vieux de 15 ans : ce post de [anandtech] qui disait en janvier [2004] avoir une photo de Tejas alors que mes sources affirmaient que Tejas n'avait jamais tape-out. J'ai retrouvé le CPU ... et c'est un Prescott B0 ES.|trans-title=I finally solved a 15-years-old mystery: this anandtech post saying in January [2004] to have a photograph of Tejas whereas my sources stated that Tejas was never tape-out. I found the CPU ... and it's a Prescott B0 ES.}}</ref> Most probably only thermal samples of Tejas were produced.