The Central Processing Unit

Upgrading or purchasing a computer today requires that the buyer know more about what is inside the main box than in previous years. With competing technology and the emergence of non-Intel™ central processor units (CPUs) some computers are as different as day is to night when it comes to the components used. In years past Intel based computers always assured compatiblity and reliability when compared to the other brands. That is not the case today. CPU makers such as AMD, Cyrix and IBM (licensed Cyrix technology) are producing CPUs that perform at or above the benchmark levels of their Intel counterparts and at significantly reduced prices.

We have been asked countless times which system we would prefer. If money was not a consideration, we would definately go for a Pentium II with a 100 Mhz system bus, but in reality this webpage is being authored on a Cyrix MII 300 based computer system for a simple reason...saving money. We run many different systems and as an assembler we must keep up with the current speeds so our in-house upgrades in the past year or so have all been based on the Cyrix systems. There is no significant lag in performance and there have been no compatibility problems encountered with any applications. Some folks in this industry say the Socket 7 based systems are history, but that is not true when there are major manufacturers supporting the Socket 7 and Super Socket 7 (100 Mhz system bus) platforms. Without the Socket 7 platform we would be facing higher cost for system performance.

Compatibility or specifically...IBM compatibility became the catch phrase and benchmark for the majority of the personal computing industry. Today it is DOS or Windows compatibility that defines what you need to make sure you can run the majority of programs bought off the shelf in the personal computer arena. Compatibility is no longer an issue with the AMD and IBM/Cyrix CPUs.

The Intel Celeron processor is another story all together. It is Intel's low price answer to the clones. A Celeron processor is basically a stripped down Pentium II processor and it's preformance reflects it. The Celeron based system is not a bad system it just doesn't match up to the clones performance in our opinion.

The Central Processing Unit (CPU) is basically the brain that crunches all the numbers while you play games or work on your computer.

For the past several years the CPU was based on the square socket cpu with a lot of tiny pins that plug into the socket. Socket 7 is the most recent standard for the square type cpu.

Intel introduced new technology with the Slot 1 Pentium II cpus that use a different and at the present time, more expensive architecture.

The 100 Mhz system bus was introduced for both the Socket 7 and the Slot 1 motherboards allowing another leap in performance from the standard 66 Mhz system bus.

100 Mhz System Bus - In simple terms, this is the speed at which the motherboard operates. Up until late 1997 all Windows compatible systems operated on a system bus at 66 Mhz. This is not to be confused with the CPU speed which could be anything from 166 Mhz to 450 Mhz at the time of this writing. Since the system bus is the device that carry's the flow of instructions and data the computer operates at a faster base level. In Socket 7 systems a 100 Mhz bus is referred to as a Super Socket 7 motherboard. In Pentium II systems the system bus and the SDRAM (DIMM) memory must be matched at 100 Mhz for proper performance at 100 Mhz system bus level. Both type of systems come in 66 Mhz and 100 Mhz versions.

RAM Memory - Comes in two distinct flavors. The old standard 72 pin SIMM (Simulated Memory Module) and 164 pin DIMM (Dynamic Memory Module). The SIMMs come in standard FPO (Fast Page Output) or EDO (Extended Data Output) running from 60 to 70 nanoseconds (ns). DIMM can be matched to the 100 Mhz system bus and runs in the 5 to 10 ns range. DIMM is also referred to as SDRAM. SDRAM DIMM is a faster memory than EDO or FPO SIMMS.

AGP or PCI Video - AGP video is much faster than the 32 Bit PCI video and requires a special slot on the mainboard to function. AGP is the choice for high performance.

Integrated Sound or Sound Card - This really doesn't matter as long as the integrated sound chip is a quality chip such as Creative Labs, OPTI or Yamaha. If the sound goes out on the motherboard, you can disable the sound chip in the CMOS setup and replace it with a sound card. MAKE SURE you can disable the integrated sound chip before purchasing any mainboard with integrated sound as it could take a mainboard upgrade to repair the sound if the chip cannot be disabled. We have never come across any integrated sound chip that could not be disabled as of this writing.

Serial Mouse or PS/2 Mouse - Again, it really doesn't matter except that serial mice are more prevalent and easier to find in any discount store and computer dealer. Using a PS/2 mouse can free up a 9 pin serial port if the port is needed for another application.

Mainboard Form Factor - AT is the most common form factor for personal computers. ATX allows automatic power-up and power-down applications as described in Power Supply below.

Power Supply - Considering all the components in a modern multimedia system (cdrom, hard disk, etc.) it is best to never go below a 230 watt power supply. Power Supplies come in AT and ATX form factors in regards to the mainboard plug-in. ATX power supplies can completely power down the system when Shut Down is selected and they can be setup to startup on a series of telephone rings if the BIOS support such a feature. Be sure to know if you have an AT or ATX mainboard before purchasing a replacement.

ISA 16 Bit Slots & PCI 32 Bit Slots - The ISA slots (usually black) accept 16 BIT ISA cards such as modems, video cards and other devices. ISA is an older, slower standard, but most modern computers still have at least two ISA slots. PCI slots (usually white) accept the same types of devices in a 32 bit standard.

Universal Serial Bus - The next generation in plug-in standards. Allow HOT PLUG (plugging in a device while the computer is running) devices such as video and digital cameras. Also keyboards and many other items. Could become the standard for most peripherial devices within a few years. Best to make sure your new upgrade or system is USB capable.

Case - Desktop or Tower is a matter of personal perference. Technicians had rather work on a tower system as most components are easy to get to.

ISA or PCI Modem - If you get a Pentium II system that is at least 266 MHz or a clone system of at least 300 Mhz then the PCI 32 Bit modems are fine. Otherwise, stick with the 16 Bit ISA modem as it has it's own built in processor and doesn't rely on the CPU as much as a PCI modem device.

When considering an upgrade or system purchase you need to take the following items into consideration:
CPU and Motherboard Type: Socket 7, Super Socket 7 or PII	Motherboard Form Factor: AT or ATX
RAM Memory - DIMM (5 to 10ns) or SIMM (60ns)	How many ISA 16 Bit slots are needed?
Accelerated Graphics Port Video or PCI Video	How many PCI 32 Bit slots are needed?
Integrated Sound or Sound Card	Universal Serial Bus
Serial Mouse or PS/2 Mouse	Type of Case: Tower or Desktop
Power Supply Minimum : 230 Watt	ISA Modem or PCI Modem