Cyrix 5x86
In August 1995 the Cyrix company brought out the Cyrix 5x86, one of the last and fastest microprocessors for socket 3 - the last CPU socket of the 80486 generation. With its construction and its good price-performance ratio, the processor was intended for upgrading older systems. As usual with Cyrix, this CPU was again sold by the manufacturing partners under their own names as IBM 5x86 and ST 5x86.
classification
The move to the fifth generation of processors began in the mid-1990s. However, models such as the Pentium were incompatible with all previous socket types. The acquisition of a powerful CPU thus entailed the purchase of a complete computer. The Cyrix 5x86 should start right there: a CPU with the performance of a Pentium, which could also be used in existing older mainboards .
Technical
In contrast to the AMD Am5x86 introduced at the end of 1995 , the Cyrix 5x86 already has many features of the fifth generation. Parts of the design were taken from the later Cyrix 6x86 . This makes the CPU a real advancement compared to fourth generation CPUs. This is also evident from the fact that the Cyrix achieves the performance of an Intel Pentium 75 at around 100 MHz, while the Am5x86 needs 133 MHz for this. This is primarily due to the high FPU performance. This means that it is not possible to objectively classify the CPU to the fourth or fifth generation.
In order to position the CPU in the Pentium market, the two best-known models were given a model rating called P : the 5x86-100 (100 MHz = 3 × 33 MHz) with P75 and the 5x86-120 (120 MHz = 3 × 40 MHz) with P90. There are other, but rather rare, variants. The fastest version with 133 MHz (4 × 33 MHz) did not go on sale and was only sold to suppliers of upgrade modules for a short time. In this case, there was only one upgrade option, as the increased operating voltage of 3.7 V was only possible with a suitable intermediate socket and no current mainboards with setting options above 3.45 V for socket 3 appeared.
In Germany, the 5x86-100GP was widely used with the first Aldi PC sold in 1995 .
Model data
- Code name: M1sc
- Sold as: Cyrix 5x86, ST 5x86 and IBM 5x86
- L1 cache: 16 KiB (unified)
- L2 cache: depending on the equipment on the main board used
- Socket 3 with a front side bus from 25 to 40 MHz
- Operating voltage (VCore): 3.45 V (3.6 V on some 120 MHz models; 3.7 V on 133 MHz models)
- Manufacturing technology: 0.65 µm at IBM
- The size: 144 mm² with 2 million transistors
- Versions:
- 80 MHz (2 × 40 MHz) as 5x86-80GP
- 100 MHz (3 × 33 MHz) as 5x86-100GP (P-Rating P75)
- 100 MHz (4 × 25 MHz) as 5x86-100GP / 4x
- 120 MHz (3 × 40 MHz) as 5x86-120GP (P-Rating P90)
- 120 MHz (4 × 30 MHz) as 5x86-120GP / 4x
- 133 MHz (4 × 33 MHz) as 5x86-133GP / 4x