IA32 Architecture Family
- (Information taken from the Intel manuals to give an overview over the individual generation's capabilities.)
Intel Processors
This table shows briefly the features of each x86 CPU Intel has made. Items marked Yes are in all processors in that series, No means not (obviously), and Maybe means that some processors have it (usually later steppings). Note: For the moment this only shows Intel processors, and a lot of processors are incomplete. Wait a while, all will be revealed. JackScott 10:19, 3 March 2009 (UTC)
| Release Date | FPU (80x87) | MMX | PAE | SSE | Hyper-threading | EM64T/AMD64 | SMP | |
|---|---|---|---|---|---|---|---|---|
| 8086 | 1982 | No | No | No | No | No | 16bit | No |
| 286 | 1982 | No | No | No | No | No | 16bit | No |
| 386 | 1985 | Maybe | No | No | No | No | No | No |
| 486 | 1989 | Yes | No | No | No | No | No | No |
| Pentium | 1993 | Yes | Maybe | No | No | No | No | Yes |
| Pentium Pro | 1995 | Yes | No | Yes | No | No | No | Yes |
| Pentium II | 1997 | Yes | Yes | Yes | No | No | No | Yes |
| Pentium II Xeon | 1998 | Yes | Yes | Yes | No | No | No | Yes |
| Pentium III | 1999 | Yes | Yes | Yes | SSE | No | No | Yes |
| Pentium III Xeon | 1999 | Yes | Yes | Yes | SSE | No | No | Yes |
| Pentium IV | 2000 | Yes | Yes | Yes | SSE2/(3) | Yes | Maybe | Yes |
| Pentium M | 2003 | Yes | Yes | Yes | SSE2 | No | No | Yes |
| Core | 2003 | Yes | Yes | Yes | SSE3 | No | No | Yes |
| Xeon 51xx | 2006 | Yes | Yes | Yes | SSSE3 | Yes | Yes | Yes |
| Core 2 | 2006 | Yes | Yes | Yes | SSE3 | No | Yes | Yes |
| Xeon 54xx | 2007 | Yes | Yes | Yes | SSE4 | No | Yes | Yes |
| Core i7 | 2008 | Yes | Yes | Yes | SSE4 | Yes | Yes | Yes |
| Atom 200/300 | 2008 | Yes | Yes | Yes | SSSE3 | Yes | Yes | Yes |
| Atom N-series | 2008 | Yes | Yes | ? | SSSE3 | Yes | No | Yes |
| Atom Z-series | 2008 | Yes | Yes | ? | SSSE3 | Yes | No | Yes |
These processors from Intel use the CPUID string "GenuineIntel"
Intel 386
Successor to the 80286, the Intel 386 is the first processor of the IA32 architecture. It has 32 bit wide registers, supports 4 kByte paging, and a flat memory model in addition to the segmented memory model of the 80286.
Intel 486
The 486 integrates a 80x87 FPU on-chip, and supports power saving functions (System Management Mode, Stop Clock, Auto Halt Powerdown).
Pentium
The Pentium supports 4 MiB paging in addition to the usual 4 kByte paging, integrates an APIC and (in later steppings) MMX SIMD registers (single instruction, multiple data). It also supports 2-way multiprocessing.
Pentium Pro
The Pentium Pro supports PAE (36 bit address space), but does not have the MMX registers of the Pentium.
Pentium II
The Pentium II again supports MMX (as well as PAE), as well as additional low-power states: AutoHALT, Stop-Grant, Sleep, and ~DeepSleep.
Pentium II Xeon
The Xeon supports 4/8/+ way multiprocessing.
Pentium III
The Pentium III supports SSE (128 bit packed single FP SIMD).
Pentium IV / Pentium M
The Pentium IV as well as the (mobile) Pentium M both support SSE2; the Pentium IV also supports Hyper-Threading (one-chip multiprocessing).
Core 2 Series (Duo/Quad)
Core i7 Series
Atom Series
Advanced Micro Device Intel-compatible Processors
The biggest competitor to Intel at this time (2004 August). They came into being slightly after Cyrix with a 5k86 (being a 486 compatible similar to the 5x86, don't confuse them) and then followed it up by a K6 processor. This one was faster than the Pentiums, and more popular than the Cyrix ones because they both didn't rate it (afaik), and they didn't overheat (as was claimed, untrue, for the Cyrixes).
The CPUID identifier string is "~AuthenticAMD"
K6
The K6 processor was a very nice processor, being Pentium compatible and doing anything the Pentium half could. It became impopular because it was too damn fast, it did a LOOPcc within 2 cycles, where the Pentiums took 18 cycles.
Because software couldn't handle the sheer speed, it made errors, and thus caused frequent "Blue Screen"s. Microsoft issued a K6 patch which was mandatory for all K6 users.
K6-2
AMD had a lesson learned there, don't make your processor too fast in some instructions. Not that they were put off by that, they just added 16 wait states to the execution of the LOOPcc and thus caused it to slow to the speed of a Pentium. AMD didn't just do this however. They added a special case (speculation, might be coincidence) for the DEC (E)CX; Jcc combination, which is semantically equivalent with the LOOPcc instruction, but this semantic equivalence and the loop being faster on Intels caused the loop instruction to always be used. Nobody used the DEC/Jcc combo. They kept the original speed for this combo and specified in their optimization manuals that this was the preferred method over the loopcc instruction.
It also featured a new technology, the 3DNOW! technology, which was MMX using floating point numbers, and multiplexed (again) on the floating point registers. The K6-2 was quite popular, and scaled higher than the P1 ever did. It was largely compatible with the P2, but (afaik) not completely.
K6-3
They started this design off with the concept of not making it underpowered in any place, and to make it at least P2 compatible. It was fully P2 compatible.
The K6-3 was not too popular, mainly because the K6-2 did very well and people didn't see why they should buy a more expensive K6-3 for the same amount of megahertz. This of course was a joke, same as it is to call a 2GHZ opteron slower than a 2.2GHZ celeron.
A little known fact about the K6-3 is that it is in fact an Athlon, minus a few instructions, and minus one very important piece. The K6-3 suffered from a bottleneck at the instruction decode unit (which converts the X86 instructions to native instructions). It could only handle 2 in a cycle, which it made during about 20-30% of the cycles for average software. For optimized software you could bring it to 100% easily, and still want another channel. This wasn't too weird, because it did have 3 execution units of each type (ALU / MMX / loadstore) which were not used much at all. Note that these units are units executing the native instructions, so making 3 of each is not a stupid idea. They needed a new front end, and of course a new copy of instructions from Intel.
Athlon (first try)
The first models of the Athlon were distinct, they were the first time that a competitor to Intel actually had a faster processor, without Intel having a backup plan. It was poised against the PIII, which at that time was their top model and best-running one too. The athlon beat them to the 1GHZ mark, and at that time the 1GHZ had become completely irrelevant. It just meant that they had a new size to mark their processors with. Intel missed the point here, and they did until very shortly ago. The GHZ myth had been broken, the Athlon at 1.1GHZ was still faster than the PIII at 1.3GHZ, and people knew. They didn't go for a P3 if a faster athlon was available at a lower clock speed, and at a lower price.
Athlon XP / MP / Duron (new style)
AMD switched to a big offensive, trying to persuade the buyers to demand AMD CPU's instead of being OK with Intels. The new versions of these processors were all just a tad better than the previous one, could do a slight number of instructions more (the Athlons started with not even SSE1, and from model 6 (both Athlon and Duron) they supported it). The processors also advanced very slightly in each other direction, making each new type just a tad faster than the previous one. In the end of the GHZ wars (past year, about) the fastest Athlon was running at 2.2GHZ, but outperformed the better half of the 3GHZ P4's.
AMD64 based CPU's
This is slightly offtopic here, but still quite relevant, since these processors all support the entire IA32 family natively. AMD created a new processor, with 64-bit (actually 48-bit, but who notices those 16 bits?) memory addressing and 64-bit calculations, being very compatible with the old style CPU's. So compatible, that the core for 32-bit and 64-bit is essentially equal, aside from the size of calculations and the support of a few encodings that were in effect redundant. They removed a few 1-byte opcodes (about 20 in total, including all 1-byte INC and 1-byte DEC instructions) to make place for a new REX prefix. They modified it to use 16 registers instead of 8, added a load of new names, got the old software working, and optimized the 32-bit performance to unprecedented levels. These CPU's outperform the P4 at any clock speed, in almost (1/20 programs not) any calculation-intensive program. This made them very popular, but also very expensive, The cheapest nowadays is around 180 dollars, or euro's.
Other CPU vendors making similar chips
Cyrix
Cyrix was a well-known CPU vendor from the 386 years (and slightly before) up to the Pentium II times, when it more or less vanished inside Via. Via now uses the name as a CPU name (not making it clearer), but this section is about the Cyrix CPU's. The processors supporting CPUID call it a "CyrixInstead"
Cyrix 387
This isn't actually a processor, but is the most famous Cyrix processor. It was the fastest coprocessor to the 386 to be found, and was even very usable aside a 486-SX. These were the main line of money for Cyrix.
Cyrix 4x86
A processor that had the abilities of a 486. The first generation plugged into 386 sockets giving greater speeds without requiring extra hardware updates. Later editions could also be used on 486 motherboards.
Cyrix 5x86
A processor that performed as a 486 and was socket-compatible. It features some of the pentium's abilities, but not all (such as cmpxchg8b).
Cyrix 6x86 / M1
This processor is, even though the name suggests otherwise, compatible with the 586 (Pentium). It didn't contain any of the MMX or PPro features but is nevertheless very nice. It performed slightly better per cycle compared to the Pentium Pro, and was thus given ratings. This was the time they were loathed for rating their processors, since the performance of floating point operations was lower than that of the Pentium Pro
Cyrix 6x86MX / M2
Was a Pentium MMX compatible processor, also using ratings which gave it a bad name to start with. It was again socket-compatible to the Pentium MMX and the older Pentiums (without MMX). It supported a few features from the Pentium Pro, among which the very usable CMOVcc set. This however wasn't well known at the time, and nobody seemed to care.
MediaGX
This was a chip that apart from the CPU, included several peripherals on-chip including graphics and audio devices.
The company was bought by National Semiconductor, who sold the trademark to VIA. The MediaGX was developed further and was eventually bought by AMD who marketed it as the Geode.
Rise Technologies
I've only heard about this company making Pentium-compatible chips, without MMX, but I don't know any detail but the CPUID identifier string. It just stuck. The string was "RiseRiseRise", or the same in all 3 dwords (making a search for it very easy).