An AMD Am386 SX33 on a typical 386SX-motherboard. The difference between SX and DX in the 386 range is the width of the bus. 16-bit for SX and 32-bit for DX. The 16-bit wide motherboards were cheaper to manufacture and usually look a lot like 286 motherboards (that are 16-bit, too). Actually the 16-bit performance of a 286 and 386SX is quite comparable with the 386 having the convenience of easier memory management for your base memory in DOS.

The AMD 386 is pin-to-pin compatible with Intel's 386SX. Although this CPU is soldered like most 386SX's so upgrading the CPU wasn't an option. Upgrading the CPU also meant increasing the clock-frequency of the motherboard and not all chipsets could run at 40MHz.

This particular motherboard is fitted with an Intel 387SX math co-processor. Something unusual in it's time, especially on SX motherboards. > Read more

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A typical 386SX motherboard with a AMD Am386 SX40 fitted. The chip is dated 31 week 1994 so this this was used for a budget system of it's day. I guess the 40MHz clock favored the sales somewhat since a higher clock is often regarded as a faster system. Nevertheless, the 386SX in essence isn't really faster than a 286 (hypothetically at 40MHz).

I haven't benchmarked this motherboard yet but did run benchmarks on a different one with different chipset. See the benchmark link for the results. > Read more

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The 'Magix' motherboard on which this 386SX20 is fitted can run with 0 wait-state (0WS) memory and gets incredibly high memory bandwidth. Both the chipset and the 0WS form the base for this kind of performance.

For a 386SX20 it's a fine system to deal with, however, in the benchmarks another 386SX20 is included that scores better in all applications except memory bandwidth. The reason is simple; the other SX20 runs with 16KB on-board cache! Cache increases all-round performance and was quite expensive back in the day. It's unusual for a low-clocked 386SX to have cache at all so the performance figures for the 386SX with cache are uncommon. > Read more

A 386DX40 in QFP package that is soldered directly to the motherboard. It's fitted on an Octek Jaguar V motherboard which is one of the later 386 boards from the era of affordable 386 DX40's. In the day you could buy DX2/66's with far greater performance- but also a high pricetag. The a good 386DX40 was a great alternative to low-end 486's. Especially if you had motherboards with extra cache (which the Octek Jaguar V doesn't have). > Read more

Practically identical to this DX40. > Read more

Fastest normal/true 386SX around. Despite that a 386SX40 works just fine it's does not perform that fast. 40MHz in 386DX or 486-terms really is a lot faster.

Of course a lot depends on the application you run but a 386DX at just 25MHz can be about just as fast. Not to mention a DX33 or DX40; they are so much faster to work with.

The difference all boils down to 2 notable things: the 386SX has a 16-bit memory bus instead of 32-bit for the DX and most 386SX didn't have external cache whereas a lot of DX's already came with 64k or more. > Read more

Just like this SX33 but fitted on a motherboard. > Read more

I have a bunch of these DX40's; apparently they are sold in great quantities back then as it's not difficult to get hands on one even today! In 1992 an Am386DX40 was a good choice: fast, reliable and pretty cheap. > Read more

Just like this DX40; the fastest kind of 386 made.

AMD's 386 was a clone of the Intel 386. Back in the days AMD used to manufacture Intel chips (8086 to 80286) but Intel didn't allow AMD to manufacture a 386. The initial contract didn't state that AMD was allowed to manufacture 386 CPU's. AMD and Intel spent some time in court and finally AMD was allowed to manufacture 386's after all.

By the time AMD was shipping out their 386 CPU's, Intel already had (expensive) 486 CPU's available. > Read more

See this Am386 33MHz part for benchmarks. More information about the AMD 386 can be found here. > Read more

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A nice little 20MHz part from Q3 1990. Not a bad chip but too expensive in it's day for most people. 286's were still very common and many DOS applications ran just fine on them. The 25MHz and 33MHz models became more affordable in the '91. As a bonus the 33MHz part is vastly better than the 20MHz part. > Read more

A 386 in with the classic Intel i386 logo. This model runs at 20MHz and features the 32-bit external bus (instead of 16-bit like the 386SX). Back in the day when the 386 was new you would find the DX20 fitted in expensive systems, but by late 1990 when this CPU was made, a decent system would already be fitted with a 33MHz part.

However, I guess a lot of people would still end up with a 286 or 386SX. > Read more

Just like the 16MHz part but 4MHz faster. 4MHz may seem a little but it really adds up with these kinds of CPU's. > Read more

Back in 1987 this CPU was just 2 years old on paper (386 being launched on October 1985) but less than one year old in terms of availability (386 being available in third quarter of 1986). Consider that this CPU could already do 32-bit jobs at a whopping 16MHz, while Europeans just started buying 8MHz 8088-based computers. By the time people shifted to the 286 CPU's the 486 was already making its debut. Now compare this situation to today's market ... . > Read more

The fastest 386 ever made! It runs at a whopping 40MHz which means it also uses a 40MHz bus. This together tremendously increases the speed of the computer. Combine it with a Vesa Local Bus graphics card and I think it can be faster than the budget, but more expensive, 486 systems.

AMD released this 40MHz part at the time when the 386 was mature. Motherboards were more advanced and could be build with a few components (opposed to the older big motherboards which have a lot of little chips). Those motherboards could run at 40MHz without causing trouble with latencies. > Read more

AMD's version of the 386SX. It's not much different compared to the 386DX from both AMD and Intel. The SX versions are 32 bits internally but have a 16 bit external bus for communication with memory, chipset and such.

I probably mentioned it elsewhere but: don't confuse the SX/DX from a 386 with the SX/DX from a 486. They don't mean the same. Both the 386SX and 386DX don't have a FPU (co-processor). The 486SX and 486DX both have a 32 bit external bus but the SX doesn't have a co-processor. The 486DX is 'full-blown' and has a co-processor built-in. > Read more

A lot like the 33MHz model. The only noticeable difference is the clock frequency and the description on the CPU is in white letters. Normal Am386 CPU's in ceramic packaging use black letters. > Read more

Just like the 16MHz model but 4MHz faster.

This CPU has no sSpec number but does show 'C STEP'. This stands for C stepping.

In reality the 386SX20 is not much faster than a good (16MHz/20MHz) 286. However, the 386SX benefits from being able to run (32-bit) Windows 3.1 properly and to use memory managers like EMM386 which makes it a lot easier to free up conventional memory.

Also this chip is fitted on a motherboard with 16k cache. Quite unusual for a low-end 386 but it does increase performance. Another difference (depending on motherboard/chipset and memory speed) between 20MHz 286 and 20MHz 386SX's can be the memory wait-state. A system with 0 wait-state (NG80386SX -20 (OPTi82C/0WS) in the benchmarks) is a lot faster than the same system with 1WS. > Read more

The slowest official released desktop 386SX out there! Running at a magical 16MHz. This CPU runs in a Hyundai Super 386SE machine with 40MB P-ATA harddrive which just fits in the picture of the whole machine. Along with four 256KB RAM 30p SIMM modules you'd be one of those guys out there that would never run out of memory!

Did I say slowest 386? I have to mention that there are 12MHz 386 CPU's out there but as far as I know these are pretty rare and never been officially released. > Read more

A fully 32-bit 386DX running at 33MHz. Both CPU as motherboard run at this frequency.

The CPU runs fine and is the second fastest 'real' (no extra cache or multiplier like a few Cyrix or IBM parts) 386. The fastest part is the Am386DX40. > Read more

The 386 was the first CPU that could do real protected mode and could run in 32 bit mode. The 286 could switch to protected mode as well but not back to real modus without resetting the processor. It's successor can switch back without a reset. This allowed the programmers to create programs that could use the protected mode.

Because the 386 was fully 32 bits it was very expensive. This lead to the creation of the 386SX (the normal 386 was called DX) which was 32 bits internally but had a 16 bits bus. Practically the same story as with the 8086 and 8088 which was 16 bit internally and had a external 16 bits and 8 bits bus respectively. Also don't confuse the SX/DX-story of the 386 with the 486. Both the 486SX and DX were fully 32 bit but the SX part lacked a maths co-processor. If you wanted a co-processor for your 386 you had to buy an additional 387 processor and install it along with your 386DX or 386SX.

This 386DX/25 is fitted on a Shuttle HOT-386A motherboard without additional cache. The motherboard runs solid and has several unusual BIOS (They call it XCMOS) settings which are better left alone. I did set the memory to 0WS and enabled Fast Gate A20. Defaults are 1WS and that setting will hurt performance quite a bit (1FPS in Doom, 3.6FPS vs. 4.6). > Read more

25MHz may not sound much, especially as it's an SX processor but bear in mind that 5MHz or 9MHz extra will boost applications with quite a big leap. After all; 5MHz is 1/5 of the total clock frequency and along with an increased clock frequency the front-side-bus goes up with 5MHz as well. Unfortunately the 386SX performed quite poor in real 32 bit applications because of the 16 bit bus. 'Talking' to memory and other parts in the PC is just a lot slower compared to an DX system with 32-bit I/O. Especially compared to 33MHz or even 40MHz 386DX systems that again have a lot more MHz at their disposal.

According to Microprocessor Report of May 6th, 1992, Intel initially planned to sell the 386SX at just 16MHz and 20MHz. The faster clocked systems that were aimed at the high-end market would either run a 386DX or 486. Since AMD took a lot of share in the 386 market with higher clocked 386SX CPU's (25, 33 and even 40MHz), Intel also ramped up their SX-line to 25MHz and 33MHz. It was said that Intel had to offer faster 386SX CPU's for Compaq otherwise Compaq would start offering AMD CPU's as well.

This particular 386SX-25 (as seen on the picture) does indeed house inside a Compaq Prolinea 3/25zs. > Read more

The IBM 386DX looks different because it has an aluminum top instead of plastic or ceramic. The chip inside is still the same as in the Intel 386 processors.

I pulled this chip from an IBM-PC that stopped working. Because I have no motherboard with a 40MHz oscillator crystal (needed for 20MHz operation) I can't benchmark it. However, the CPU runs fine with turbo-off in an 33MHz motherboard but then it'll run at only 8MHz. > Read more