Top 10 Considerations when purchasing your next Socket 7 Motherboard

Written by Tom Moran

Is a Socket 7 Motherboard for you?

The biggest question to ask yourself is "what slot architecture makes the most sense for your computing needs?". Slot 1 or Socket 7? Some industry pundits will say that the Socket 7 architecture is dead. If this is true, then why are a ton of compelling Super Socket 7 designs just being released? Why does AMD, Cyrix and IDT have a bunch of new processors in the works that utilize this form factor? There are a bunch of reasons why you might find yourself looking at a socket 7 motherboard as opposed to a Slot 1 form factor. Here are a few that come to mind.

A Socket 7 motherboard is for you if:

- Business application speed at the lowest cost is your primary concern

• You want to take part in the revolution of the 100Mhz bus speeds at the lowest prices.
• You want to have processor options from more than a single company.
• You wince every time you see some dorks in bunny suits dancing to some cheesy disco song.
• You like voting for the underdog with your hard-earned dollars.
• Your rebellious nature wouldn’t allow for anything else.
• Insert your own motivation here!

1.  Choose your chipset

The chipset your motherboard is based around is the number 1 factor I consider when buying a new motherboard. This is the heart of the board and will dictate much of what is possible in terms of bus speeds, high performance slot availability (i.e. PCI or AGP), hard drive interface types, processor support, etc. The hottest comers on the market are the newly released VIA chipset the MVP3 and the upcoming ALI Aladdin 5 chipset. These comprise the Super Socket 7 cream of the crop. These can be thought of as the most feature rich and modern of the newest socket 7 chipsets supporting the 100MHz memory bus speed, AGP video and other state of the art features. The advantage of these newer chipset designs is that you can get a board that’ll support your older processor and memory and eventually have a great upgrade path when the newer features can come into play.

2.  Which processors are supported

The number of processors on the market and the need for a number of voltage and speed configurations for different processors makes it imperative to understand what settings are being offered and which processor you want support for. A visit to various motherboard manufacturers websites will usually give an "officially supported" list of CPUs. Often times, new CPUs are not "officially" included and it’s necessary to research yourself what the voltage and CPU multiplier settings requirements are for the CPU you desire to use in the board.

Voltage requirements are broken down into "single voltage CPUs" and "split voltage CPUs". Each CPU has some positive voltage pins and some ground plane pins. To cut down on the power consumption and thus heat, most newer CPUs require a low voltage for the inner core circuitry and a higher voltage feeding the I/O section of the device known as the outer core. The original Pentium and the current IDT WinChip CPUs need one voltage for both the inner and outer core circuitry. Most of the other MMX enabled CPUs requires dual voltage plane support (i.e. AMD K6, Cyrix 6x86MX, Pentiums with MMX, etc).

For maximum flexibility, get the largest voltage range possible (for both the inner and outer core settings) with the smallest increments between each step. The multiplier settings should go up to at least 5X and beyond. The higher the multiplier possible, the better chance you’ll have upgrade possibilities.

The type of memory supported and number of slots available is a major consideration when considering a new motherboard. Support for EDO DRAM is rapidly disappearing from the newest socket 7 motherboards. A few of the newer offerings support only 168 pin SDRAM modules and have no 72 pin memory sockets on them at all.

If you want to carry over some older 72-pin memory modules to a newer board, do your research. Some boards still have 2 and even 4 72-pin sockets, so upgrading gradually is a total possibility. The reason for the disappearance of 72-pin modules, is that fast SDRAM is needed in the 100MHz bus speed designs and the typical EDO modules won’t handle it. Carefully weigh what memory you currently have and how much more life you plan on getting out of it. If you are getting a new motherboard with new memory, get only fast 168 pin SDRAM modules (preferably less than 10nS speed grade).   When in doubt about which DRAM to purchase, buy American DRAM (perferrably Micron if you want to get the best!).  They are testing their PC100 modules up to 125MHz.

The most flexible motherboard designs can give you separate control of the processor speed and the main memory bus speed. This means that you might be able to run your new K6-300 at 3x100MHz and still keep your memory timing speed at the older 66MHz bus speed for older/slower memory (a nice feature for those who like to squeeze life from existing memory).

The idea of an asynchronous timing mode was first introduced with the Cyrix 200MHz processor that required a 75MHz bus speed (75 x 2 = 150MHz, which was considered a PR rating of 200MHz). By requiring a 75MHz bus speed, the PCI bus would then be running at 37.5MHz which is over the PCI bus spec of 33MHz. Overclocked PCI busses caused system instability for many people and the ability to run the memory bus speed at the official 66MHz while the processor was getting 75MHz helped many users.

This is the same concept when trying to run 100MHz bus speed. Even if your memory can handle 100MHz, the typical way of deriving the PCI clock speed (bus speed/2) would yield an unworkable 50MHz. So designers have to provide the speed in some areas and allow for cutting back the speed in other areas. Look for the most flexibility as possible in this area. It may help overclocking, to be able to control the speed of various system components.

5.  Availability of expansion slots

Count up the number of cards you have and what type of slots they need and you’ll know how many slots you need of either PCI or ISA or even AGP. Consider any planned expansion you might add in the near future (SCSI board, PCI or AGP video accelerator card, internal modem, etc). Many motherboards have a shared ISA and PCI slot. This means that only one or the other can be used at any one time. Don’t count on using both the ISA and PCI slot that is in a shared arrangement. The more slots for later expansion the better.

The form factor of your case will most likely decide whether you get an AT or an ATX motherboard layout. The AT form factor is still available for anyone who has an older case and still wants to use it. For everyone who is going for a new case, get ATX. The ATX advantages include: easier to configure cabling, elimination of cheap serial/parallel I/O cables that plug onto the motherboard, better clearance usually for full length cards and generally a cooler layout.

Between AT designs the critical difference in layout revolve around how many full length cards can be used (usually very few, if at all, due to the processor/fan and heatsinks/regulators) being in the way. Another factor is how packed is the I/O cabling section. It may only manner during initial setup, but some boards place the IDE and serial/parallel port connectors so close together it’s hard to get them easily plugged in without your fingers getting contorted resulting in possible cable header misalignment.

A small annoyance factor with all motherboards is the hoops you’ve got to jump through in order to get them setup correctly. This usually comes in two flavors, the SOFT BIOS setup and the hard jumper approach. The SOFT BIOS, made famous by Abit, is a very clean and easy way to get things setup right. Pop into the BIOS and most all of the available setups are configurable via software.

The hard jumper approach usually entails using push-on shorting jumper plugs that go over two pin headers on the board. Some motherboards are a mess of these jumpers spread out all over the board (especially nasty are those tucked under card slots or under cabling). I’d like to see more use of dip switches on motherboards. How often do you find yourself dropping those tiny jumpers and losing them inside your case?

If you like to tweak your setup and usually have your case on, you might want to look for a SOFT BIOS type of setup. If you don’t mind referencing your documentation to figure out some obscure setup and how to implement it, then this should be a low priority compared to some of the other criteria.

8.  Motherboard Manufacturer reputation

Once upon a time, there were a few very reputable motherboard manufacturers and a number of low cost, clone outfits that generated suspect quality and reliability. This situation is improving and nowadays there are plenty of excellent companies to choose from. This doesn’t mean, though, that any motherboard is as good as the next. Careful research of news groups and hardware websites will show that not all boards are created equal and let the buyer beware. Do your own research, don’t rely on hardware reviews for all your information.

My recommendation is to stay with a company who you’ve heard good things about and that have a website that features BIOS upgrades, Bus Mastering IDE drivers, manuals and various other drivers. The cutting edge products will usually have follow on drivers designed to smooth out or eliminate flaws discovered during the early part of their release. If you can’t find a website for a particular manufacturer, I’d wonder about parting with any money in their direction. What’s a computer company without a decent website.

It’s often times hard to get a decent response via email from even the larger companies, but it’s worth an experiment to email a company before you buy and see how interested they are in following up your questions.

10.  Price

Putting price last in the list may surprise some people. Anyone considering a Socket 7 board is usually someone who prides themselves in getting killer components for the least number of dollars possible. The reason price is so far down is you typically never pay a premium for the latest and greatest motherboards. Unlike processors that get introduced at extremely inflated prices and drop hundreds of dollars over time, motherboards come out and are pretty stable price wise.