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[[Image:Intel 80486DX2 bottomtop.jpg|200px|thumb|...Intel and bottom view with gold plated pins.i486DX2-66マイクロプロセッサ、正面から]]
[[Image:Intel 80486DX2 topbottom.jpg|200px|thumb|An Intel i486DX2-66 Microprocessor, top view同裏側。金色のピンが並ぶ。]]
'''Intel 80486DX2'''は、[[インテル]]が1992年に開発した[[マイクロプロセッサ]]([[CPU]])。80486DX2の基本技術は[[Intel 80486DX|80486DX]]と同一だが、これに新たに[[クロックダブリング]]と呼ばれる技術を追加した。この技術は全体の[[クロック|クロック周波数]]を[[フロントサイドバス]]の2倍に引き上げるもので、80486DX2はこれを搭載した最初のマイクロプロセッサであった。これにより80486DX2は、80486DXベースの製品を同じ周波数に換算したものよりも高速であった。
[[Image:Intel 80486DX2 bottom.jpg|200px|thumb|... and bottom view with gold plated pins.]]
The '''Intel 80486DX2''' is a [[Central processing unit|CPU]] produced by [[Intel]] that was introduced in [[1992]]. The 80486DX2 is identical to a [[Intel 80486DX|80486DX]] but for the addition of "[[clock doubling]]" technology. It was the first chip to use clock doubling, whereby the processor performs two [[clock cycle]]s per single cycle of the memory bus. Essentially, the processor's speed is set to double of the speed of the system bus. Because of this, an Intel 80486DX2 is faster than an [[Intel 80486DX]]-based system at the same processor speed; a normal DX chip performs one processor clock cycle per system bus cycle (is aligned to the same speed as the system's bus).
Intel produced two 80486DX2 [[Central processing unit|CPUs]]:
*80486DX2-50 : フロントサイドバスが25MHz、[[クロック|クロック周波数]]が50MHzのモデル
*50 MHz CPU for systems with a 25 MHz [[front side bus]]
*80486DX2-66 : フロントサイドバスが33MHz、クロック周波数が66MHzのモデル
*66 MHz CPU for systems with a 33 MHz front side bus
== The Legend of the DX2-66の伝説 ==
コンピュータが32[[ビット]]の時代に育った多くの人にとって、80486DX2-66は伝説的なプロセッサである。8MBもしくは16MBのRAMや[[VESA ローカルバス]]の[[ビデオカード]]と合わせて使用すると、当時のプロセッサの中では最速とも言える性能を発揮した。後に多くのゲームが[[Intel 486|486]]プロセッサの性能を要求したとき、DX2-66は[[SX-25]]や[[SX-33]]の性能に追いついているプロセッサとして注目された。しかし3Dのグラフィックが導入された頃からDX2-66は次第に要求が満たせなくなっていった。それでも[[Pentium]]が登場した頃も、DX2-66はPrntiumと同じ棚に並べられており、ある程度の支持を受けていた。
For most people brought up during the 32-bit era the 80486DX2-66 is a legendary processor. Often coupled with 8 MB or 16 MB of RAM and a [[VESA_Local_Bus|VESA Local Bus]] video card, they were the top tier processor when they were released, a solid mid-range configuration option soon after and a decent performer on a budget at the end of their life cycle. The DX2-66 is often remembered most because of its excellent performance on the generation of games current at its release. Soon after, as more games demanded a 486 processor, the DX2-66 shone as a solid performer overtaking the SX-25 and SX-33 configurations as the system of choice for most computers. During the end of its lifespan, with the introduction of 3D graphics, the DX2-66 started to fall behind. Nevertheless, while [[Quake]]'s system requirements listed "[[Pentium]]" on the box, a DX2-66 could comfortably handle Quake at lower resolutions.
[[AMD]] also produced an 80 MHz 'DX2' chip for systems with a 40 MHz front side bus.
It is now standard practice for a CPU to perform more than one clock cycle per bus clock cycle.
[[Category:x86 microprocessorsマイクロプロセッサ|Intel 4862]]
[[Category:x86 microprocessors|Intel 4862]]
[[en:Intel 80486DX2]]