DIFFERENCES BETWEEN INTEL CPUs                            Rev 1.0
+--------------------------+----------------+----------------+----------------+
|           CPU            |      8086      |      8088      |      286       |
+--------------------------+----------------+----------------+----------------+
|Internal Processing       |       16       |       16       |     16 bit     |
+--------------------------+----------------+----------------+----------------+
|External I/O Processing   |       16       |       8        |     16 bit     |
+--------------------------+----------------+----------------+----------------+
|MCP Present               |       no       |       no       |       no       |
+--------------------------+----------------+----------------+----------------+
|Memory Management         |       no       |       no       |       no       |
+--------------------------+----------------+----------------+----------------+
|Cache on board            |       no       |       no       |       no       |
+--------------------------+----------------+----------------+----------------+
|Speeds                    |     5,8,10     |     5,8,10     |   6,8,10,12    |
+--------------------------+----------------+----------------+----------------+
|Ave. Cycles/Instruction   |       12       |       12       |      4.9       |
+--------------------------+----------------+----------------+----------------+
|Perf % compared to 8088   |      100%      |      100%      |      244%      |
+--------------------------+----------------+----------------+----------------+
|Speed of MCP              |synched with CPU|synched with CPU|   2/3 of CPU   |
+--------------------------+----------------+----------------+----------------+
|Speed of Clock Crystal    |3 times the CPU |3 times the CPU |2 times the CPU |
+--------------------------+----------------+----------------+----------------+
|Speed of BUS              | synch with CPU | synch with CPU |       8        |
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.0           | real mode only | real mode only |real or standard|
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.1           |       no       |       no       |    standard    |
+--------------------------+----------------+----------------+----------------+
|Upgradable                |       no       |       no       |SnapIn AT, 50, 60
+--------------------------+----------------+----------------+----------------+
|More Powerful Than?       |      8088      |no IBM compatibl|8086,8088,80186 |
+--------------------------+----------------+----------------+----------------+
|Address Range             |     1 Meg      |     1 Meg      |     16 Meg     |
+--------------------------+----------------+----------------+----------------+


+--------------------------+----------------+----------------+----------------+
|           CPU            |     386SX      |     386DX      |     386SL      |
+--------------------------+----------------+----------------+----------------+
|Internal Processing       |     32 bit     |     32 bit     |     32 bit     |
+--------------------------+----------------+----------------+----------------+
|External I/O Processing   |     16 bit     |     32 bit     |     16 bit     |
+--------------------------+----------------+----------------+----------------+
|MCP Present               |       no       |       no       |       no       |
+--------------------------+----------------+----------------+----------------+
|Memory Management         |      yes       |      yes       |      yes       |
+--------------------------+----------------+----------------+----------------+
|Cache on board            |                |                |control circuits|
+--------------------------+----------------+----------------+----------------+
|Speeds                    |     16,20      |  16,20,25,33   |    16,20,25    |
+--------------------------+----------------+----------------+----------------+
|Ave. cycles/Instruction   |     4.9        |     4.9        |     <4.9       |
+--------------------------+----------------+----------------+----------------+
|Perf % compared to 8088   |     244%       |     244%       |     >244%      |
+--------------------------+----------------+----------------+----------------+
|Speed of MCP              |synched with CPU|synched with CPU|synched with CPU|
+--------------------------+----------------+----------------+----------------+
|Speed of Clock Crystal    |2 times the CPU |2 times the CPU |2,4,8 times CPU |
+--------------------------+----------------+----------------+----------------+
|Speed of BUS              |       8        |       8        |        8       |
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.0           |real, std & enha|real, std & enha|real, std & enha|
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.1           | std & enhanced | std & enhanced | std & enhanced |
+--------------------------+----------------+----------------+----------------+
|Upgradable                |System or CPU bd|    RapidCad    |       no       |
+--------------------------+----------------+----------------+----------------+
|More Powerful Than?       |     80286      |     i386SX     |     i386SX     |
+--------------------------+----------------+----------------+----------------+
|Address Range             |     16 Meg     |  4 Gigabytes   |     20 Meg     |
+--------------------------+----------------+----------------+----------------+


+--------------------------+----------------+----------------+----------------+
|           CPU            |   RapidCad     |     486SX      |     486DX      |
+--------------------------+----------------+----------------+----------------+
|Internal Processing       |     32 bit     |     32 bit     |     32 bit     |
+--------------------------+----------------+----------------+----------------+
|External I/O Processing   |     32 bit     |     32 bit     |     32 bit     |
+--------------------------+----------------+----------------+----------------+
|MCP Present               |      yes       |      no        |      yes       |
+--------------------------+----------------+----------------+----------------+
|Memory Management         |      yes       |      yes       |      yes       |
+--------------------------+----------------+----------------+----------------+
|Cache on board            |      no        |    yes, 8K     |    yes, 8K     |
+--------------------------+----------------+----------------+----------------+
|Speeds                    |      16-33     |    16,20,25    |    25,33,50    |
+--------------------------+----------------+----------------+----------------+
|Ave. Cycles/Instruction   |      4.9       |      1.95      |      1.95      |
+--------------------------+----------------+----------------+----------------+
|Perf % compared to 8088   |     244 %      |     633 %      |     633 %      |
+--------------------------+----------------+----------------+----------------+
|Speed of MCP              |   same as cpu  |     no mcp     |  same as CPU   |
+--------------------------+----------------+----------------+----------------+
|Speed of Clock Crystal    |2 times the CPU |  same as CPU   |  same as CPU   |
+--------------------------+----------------+----------------+----------------+
|Speed of BUS              |       8        |       8        |       8        |
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.0           |real, std & enha|real, std & enha|real, std & enha|
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.1           | std & enhanced | std & enhanced | std & enhanced |
+--------------------------+----------------+----------------+----------------+
|Upgradable                |       no       |i487SX,OverDrive|    none yet    |
+--------------------------+----------------+----------------+----------------+
|More Powerful Than?       | 386DX in math  |386DX generally |      386DX     |
+--------------------------+----------------+----------------+----------------+
|Address Range             |  4 Gigabytes   |  4 Gigabytes   |  4 Gigabytes   |
+--------------------------+----------------+----------------+----------------+


+--------------------------+----------------+----------------+----------------+
|           CPU            |     i487SX     |    i486DX-2    |  OverDrive-SX  |
+--------------------------+----------------+----------------+----------------+
|Internal Processing       |     32 bit     |     32 bit     |      32 bit    |
+--------------------------+----------------+----------------+----------------+
|External I/O Processing   |     32 bit     |     32 bit     |      32 bit    |
+--------------------------+----------------+----------------+----------------+
|MCP Present               |      yes       |      yes       |       yes      |
+--------------------------+----------------+----------------+----------------+
|Memory Management         |      yes       |      yes       |       yes      |
+--------------------------+----------------+----------------+----------------+
|Cache on board            |    yes, 8K     |    yes, 8K     |     yes, 8K    |
+--------------------------+----------------+----------------+----------------+
|Speeds                    |    16,20,25    |50 intrnl so far| 32,40,50 intrnl|
+--------------------------+----------------+----------------+----------------+
|Ave. Cycles/Instruction   |      1.95*     |1.95 intrnl cyc*|1.95 intrnl cyc*|
+--------------------------+----------------+----------------+----------------+
|Perf % compared to 8088   |     633 %*     | 633 % intrnl*  | 633 % intrnl*  |
+--------------------------+----------------+----------------+----------------+
|Speed of MCP              |  same as CPU   |  same as CPU   |  same as CPU   |
+--------------------------+----------------+----------------+----------------+
|Speed of Clock Crystal    |  same as CPU   |    1/2 CPU     |    1/2 CPU     |
+--------------------------+----------------+----------------+----------------+
|Speed of BUS              |       8        |       8        |       8        |
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.0           |real, std & enha|real, std & enha|real, std & enha|
+--------------------------+----------------+----------------+----------------+
|Run Windows 3.1           | std & enhanced | std & enhanced | std & enhanced |
+--------------------------+----------------+----------------+----------------+
|Upgradable                |    OverDrive   |    none yet    |       no       |
+--------------------------+----------------+----------------+----------------+
|More Powerful Than?       |     i386DX     |     i486DX     | i487SX,i486DX  |
+--------------------------+----------------+----------------+----------------+
|Address Range             |  4 Gigabytes   |  4 Gigabytes   |  4 Gigabytes   |
+--------------------------+----------------+----------------+----------------+

* On average, it takes 1.95 clocks to complete one instruction, or the i487SX
finishes one instruction 633% faster than the 8088.

In the i486DX-2 and OverDrive the reference is to the internal clock which runs
at 2 times the external clock.

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