Upgrading your motherboard
A lot of the latest motherboards are manufactured to the ATX format which has replaced the older Baby AT format. If you are upgrading your motherboard and you have the older formfactor and you want to go to ATX then you will not only need to change the motherboard but the case as well as it is a different layout. Modifying your case is difficult and, as you will also require an ATX power supply, is not really cost effective.
To identify what layout you have, see the figure below of a basic ATX system.
The points that differ from the AT case are usually:
On an ATX system:
- The CPU is next to the power supply
- The power supply fan is inside blowing over the CPU
- The I/O (Serial/Parallel) and Keyboard and Mouse Connectors are part of the motherboard (no cables)
- The power connector on the mother board is a single (DIL) connector (AT used two connectors)
Please Note: If you have an Intel Motherboard and wish to upgrade to MMX™ see the Manuals Page for compatability
A very large problem is caused because, quite often, users do not have a configuration manual with jumper settings required to upgrade the processor. ( When you buy a new motherboard [or computer] make sure you get a manual or at least jumper settings for future upgrades.) If you are in this situation and the motherboard is non-Intel manufactured (Intel manuals can be downloaded by going to the Manuals page), it is always a good idea to first have a look at the motherboard itself - a number of manufacturers screen the jumpers (switch) settings onto the motherboard so a manual may not be needed after all. If they aren't, see if you can ID the motherboard manufacturer from the BIOS and then get the manual and/or settings from this manufacturer (a fairly extensive list is available on the Motherboards page).
What speed CPU can I use?
When upgrading your CPU you must first ascertain what speed processor your system can handle. (I am sticking to Intel Pentium® processors and higher here as, to all intents and purposes, there aren't many upgrades to the 486 and below these days!) Pentium® processors will fit both a Socket 5 and Socket 7 ZIF (Zero Insertion Force) socket the difference between the two being the power rating. The socket which holds the processor on the motherboard is usually off-white (cream) in color and has raised lettering with the word 'SOCKET' followed by the number '5' or '7'.
- Socket 5 can handle Intel processors up to 133MHz (or Intel Overdrives up to 180MHz MMX™).
Intel, however, has stated that Socket 5 can, under certain conditions, work up to 200MHz. It should be noted that you must have ALL of the conditions for 200MHz to work with Socket 5. The conditions are as follows (quoted from Intel's Site):
If your system contains Socket 5, you can upgrade with the 200-MHz OverDrive processor with MMX technology if your system has:
Check with the PC manufacturer to be sure your Socket 5 system meets these requirements before upgrading with the 200-MHz Pentium OverDrive processor with MMX technology. If your system does not meet these requirements, or if you are unsure, Intel recommends upgrading with the 166-MHz Pentium OverDrive processor with MMX technology.
Installing the 200-MHz Pentium OverDrive processor with MMX technology into a Socket 5 system that does not meet these requirements can cause erratic operation, intermittent system lock-ups, decreased system reliability, and possible motherboard failure." - (end of quote)
- a voltage regulator that can supply at least 5.0 amps to the processor socket
- at least 1.75 inches (4.45 cm) of clearance above the socket
- enough ventilation to provide cooling for 17 Watts of processor power
- Socket 7 can handle Intel processors up to 233MHz1
(1Note: Some motherboards do not support above 200MHz due to the jumpers only handling up to a 3x multiplier [see below] [233MHz requires a 3.5x multiplier]).
If you are wishing to upgrade from a 'classic' Pentium® processor to MMX™ then the first thing to check is if your motherboard can handle the 2.8v core voltage required by a 'standard' MMX™ - indications that it might be MMX™ ready is that the motherboard specifications should say that it supports P55 or MMX™. If it doesn't have the necessary 2.8 core voltage then you will need to consider an Intel Overdrive processor which has a voltage regulator built in. If you are unsure whether or not your motherboard has the 2.8 core voltage and have no way of finding out but your motherboard meets all the other requirements, I recommend you go for the Intel Overdrive processor. I have seen reports of users running 'standard' MMX processors on boards without the 2.8 core voltage but for how long and how stable they are is an unknown quantity. There are adaptors available which have the 2.8 regulator on but the Intel Overdrive includes it and the overall price of the adaptor + MMX processor and the Overdrive is about the same. (You get the added security of a 3 year warranty with the Intel Overdrive which you don't get with the adaptor and any warranty you had with the standard processor would be void if the adaptor was faulty!) You will also need to see if your BIOS is MMX™ ready - this can be done by downloading Intel's MMX™ BIOS check program - if you get a negative answer you will have to upgrade the BIOS.
The Pentium® processor based motherboards, in general, have up to 3 different Bus Frequencies - 50MHz, 60MHz and 66MHz. (On some of the newer motherboards the 50MHz has been dropped). A multiplier is then used to get the correct speed for the processor.
The following table shows how the different speeds are achieved.
2Note:The 125MHz is available as an Intel MMX™ Overdrive only
Do I use STD(VR) or VRE voltage?
Intel Pentium® Processor - Pin Side (Underside)
One of the most common questions is "Do I use STD (VR) or VRE settings when I replace my CPU (processor)?". On the Intel NG they can only give a written response so I have redrawn the diagram from Intel's installation notes to simplify the description.
The CPU underside is shown below.
If the first letter after the '/' is an 'S' the voltage is
Standard (STD.or VR).
(STD = 3.135v - 3.6v)
If the first letter after the '/' is a 'V' the voltage is
Voltage Regulator Enhanced (VRE).
(VRE = 3.4v-3.6v)
For those who are interested the next letter (in this case the 'M') indicates the timing (M for min valid MD timings and S for min valid standard timings) and the last letter (the 'U' above) indicates whether the processor can be used with multiprocessing motherboards (i.e. more than one processor). If the letter is a 'U' then it has been tested for single processing only - if it is a 'S' then it has been tested for, single, dual and multi-processing.
Processor stepping is becoming increasingly important with the use of multi-processing systems and the matching of processors an integral part of a users' knowledge. Intel have fairly extensive coverage on the subject at their Developer siteand I am not going to repeat it here. Two useful direct links, though, are the Quick Reference guides for the Pentium and Pentium Pro processors.
It is also useful information if you are trying to ascertain if your processor is a 'remark'. Each different processor (i.e. 166MHz, 200MHz etc.) has stepping information unique to it's frequency. If the stepping information given at Intel's site does not match the frequency and details given on your processor then you can begin to suspect that your processor has been remarked with a higher frequency.
Information that you will require off your processor to get it's particular stepping is found on the upper side of the processor. (circled in blue on the picture below)
If you would like to get the information of your own Intel processor, then download the CPUID program from Intel. This little utility will give you information about your processor, such as whether it is a genuine Intel processor, which model you have as well as stepping info. For a full breakdown of the utility have a look at Intels' support site regarding this utility. For those interested the utilty can identify and give information for an Intel 486 through to a Pentium II. (including Pentium Pro).
Busmaster - Explanation and Drivers
Originally data was transferred via a method called Programmed Input/Output (PIO) which required the CPU to move the data between the controller card and the computers memory. Typical speeds reached were around 2.5Mb/sec. and was quite adequate for the early AT's up to the 486's. This requires a large CPU overhead and with the progress in todays applications this overhead is not desirable. Busmastering was introduced to overcome this and instead of the CPU, special controllers have been developed to handle the data to and from the computers memory. Transfer rates with Ultra DMA (see below) are now in the region of 33Mb/sec. Special drivers are required to access these controllers and they are available from Intels site. It should be noted that MS Windows 95 OSR2 has drivers included with the operating system.
Note: The above is a very basic description of Busmastering but if you want to delve even deeper you will find a lot of good info at the Intel driver site below.
Intel Busmastering drivers
(Tip: If you run into problems with the drivers, Intel have a De-install program that can be downloaded)
Ultra DMA - What is it and what do you need?
Above in the Busmastering information it was stated that transfer rates of 33Mb/s were possible with Ultra DMA. Ultra DMA is a protocol that effectively 'doubles' the route to the hard drive by transferring twice as much data per clock cycle. The previous standard (which is still current) was Enhanced IDE (EIDE) which could handle transfer rates of up to 16.6Mb/s. The Intel PCI chipsets required to handle EIDE were suffixed with FX, VX and HX and most of the drive manufacturers (if not all) produced EIDE devices.
Ultra DMA is now supported on motherboards which have Intel's TX or LX (or later) PCIset on board. However to reap the benefits of Ultra DMA there are certain factors that must be in place. Theses are (Quoted from Intel):
It should be noted that the Intel software specifications for Ultra DMA state that it requires a 'multi-tasking Operating sytem' which means that if you are running MSDOS and Windows 3.X you are out of luck - it needs at least Windows 95!
- Ultra DMA compatible logic on your system motherboard (the Intel 430TX PCIset and the Intel 440LX AGPset both contain this logic) or on a Ultra DMA PCI adapter card (for installed systems). In the case where the logic resides on the motherboard, the operating system must recognize and configure the solution.
- Ultra DMA compatible BIOS
- An Ultra DMA-aware device driver for your operating system
- An Ultra DMA compatible IDE device (disk drive, CD-ROM)
If you are considering buying a new drive I would recommend buying an Ultra DMA drive even if you don't have the Ultra DMA PCIset at present - it will work (albeit at EIDE speeds) with the older PCIsets just as the EIDE drives will work (at 16.6Mb/s max) on the Ultra DMA PCIsets.
If you are running Windows 95 and meet all the criteria above you can download a setup utility from Intels' download site (550Kb).
For more information on Ultra DMA try having a look at Intel's Ultra DMA FAQ pages.
Intel PCIsets and Motherboards Comparison
As Magenta Systems in the UK have one of the most up to date sites with this information, I highly recommend a visit to their excellent site.
Intel have a site dedicated purely to PCIsets and specification sheets of the different models can downloaded from there.
A new site that has loads of really useful info and links is Trish's Escape from Hardware Hell. A visit to her site for anyone wanting uprade info is a must!
I would also like to thank Trish for her assistance in testing and giving me feedback on the 'newlook' HOHWEB site - her input has been invaluable!