DFI-PB61-ZX Slot 1 Motherboard
Reviewed by Vijay Anand (14/4/99)

<Introduction><The Good><The Bad><Conclusion><Rating>

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Introduction

DFI is a big-time motherboard manufacturing company, as well as a few other PC-products, based in Taiwan that produces more than 300,000 motherboards per month, enough to give Asus some market competition. It's relatively a 'quiet' company with no big press-releases or fan-fare for it's new motherboards but it's strategies are quick and aggressive. Just an example; As soon as the Intel ZX chipset was released , DFI quickly embraced it with FOUR variants, involving the Slot-1, Socket-370, ATX, AT formats. If that's just the line up for the ZX chipset, what about the rest? Quite a lot more, ain't it? But what most of us don't know is that most of DFI's motherboard sales comes from the distribution channel and a small portion from system integrators. Till now, only a handful of motherboard manufacturers have come to integrate a ZX chipset and I must commend DFI for being one of the few to take the step into new waters.

For some, who are not familiar with the Intel-440-ZX chipset, it's basically a BX chipset with a crippled memory capacity and the ability to support 4 Bus-Mastering PCI devices and not 5 as in the BX chipset. Remember, the ZX was introduced for cost-conscious, general-purpose machines. The below 2 paragraphs explain to you the details.

The BX chipset is able to support up to 1GB of memory while the new ZX can only support 256mb of memory. This is the reason why you'll see up to 4 DIMM slots in the BX chipset based motherboard that has up to 8 addressing lines to cater to 4 Single or Double-sided DIMMs mixed. The ZX has only 4 memory addressing lines, therefore, motherboards based on the ZX chipset come mostly with 2 DIMM slots (with the exception of ABIT) that can take in either 2 Single or Double-sided Dimms mixed. ABIT ZX-based motherboards come with 3 DIMM slots, but they still have the same 4 memory addressing lines chipset limitation; Meaning, you can use 2 Double-sided DIMMs or, 1 Double and 2 single-sided DIMMs, or 3 Single-sided DIMMs. The reason being, Double sided DIMMs need 2 addressing lines each (Single-sided DIMMs need 1 addressing line) and these are usually the old 128mb DIMM modules or the majority of 256mb DIMM modules. ABIT sees that rarely a user will use high-capacity double-sided DIMMs and especially on a cost-conscious ZX based motherboard. But what if the user isn't aware if this and has troubles with his board if he carelessly puts Double-sided DIMMs in all 3 slots? This is why majority of the ZX-based motherboards stick with Intel's specs to provide only 2 DIMM slots to be on the safe side. DFI has taken the safe approach to avoid any problems in future, good for us! Oh and by the way, since ZX are for general cost-conscious users who don't run server-like systems with ECC memory, ECC support has been removed in the ZX chipset.

BX-based boards also support 5 PCI slot with full Bus-Mastering PCI device support but as I said before the ZX chipset limits this number to 4. Then how does ABIT-ZX boards fit 5? Simple. Not all cards and devices are Bus-Mastering Devices, so with this in mind, ABIT just added a 5th PCI-slot that doesn't have BUS-Mastering support! Now as in the above case, what if an ignorant person puts a Bus-Mastering PCI Card into THAT slot and finds that he's having problems to make it work? Therefore to be on the safe-side, sticking with Intel guidelines, most other manufacturers like DFI have just equipped it with 4 PCI slots. Less tech-support problems in future for all of them. The above mentioned 3 changes are the only things that differ it from the BX chipset.

Do note: This is the ZX chipset and not the ZX-66 chipset which only supports 66Mhz bus. So much for the ZX-chipset introduction, the contents of the box include the following: 1 PB61-ZX motherboard, 1 packet of FDD & HDD cable, Universal-Retension Mechanism (URM) for Celeron/P2/P3 cpu, 1 Drivers+Utility-CD, 1 sticker of settings, 1 motherboard-manual & 1 Guarantee Card. Let us examine the board in further detail, shall we?

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The Good

Thank goodness! DFI did not under-utilize the chipset and equipped it with 4/3/1(PCI/ISA/AGP) expansion slot configuration and 2 DIMM slots for ram. Location-wise, the main connectors like the FDD,HDD & the 2 DIMM slots are easily located in the front-right of the board. The various LED & all other connectors are clearly labeled and spaced on the board, unlike some boards who bunch them together, causing confusion. Others like the CMOS Battery, CMOS-clear jumper, SB-Link, DIP-switch block, FAN-connectors are all either located up-front or in other sensible locations (unlike the shocking Shuttle boards!). An important item that is misplaced in the majority of the motherboards is the ATX power-supply connector which is very well positioned in front of this DFI-board (All DFI boards included) and this allows proper ventilation for the tall slot-1 CPUs.

The board includes a golden-coloured heatsink over the 440BX chipset and has three 3-pin power connectors for CPU, Chassis & AGP-card which take good care of most cooling needs. An SB-Link connector is also available for some PCI cards such as the Yamaha-192XG WaveForce that gives you legacy DOS sound support. Cards such as the Creative-Live do not use this connector.

The FSB-clock and cpu-multipliers are auto-detected by default but there is a jumper to disable that and select a wide range of FSB-clocks and cpu-mulitpliers. The available FSB-clocks are 66, 75, 83, 100, 103, 105, 110, 115, 120, 124 and 133Mhz. Looks like there are some good FSB selections from the 100mhz to 124Mhz category for some overclocking! On the multiplier side, there are settings from 1.5x to 8x but it is quite useless these days as the vast majority of Celerons, P2 and P3 chips have the mulitpliers locked. But for hose who do have those old P2 chips, you also have the option of manually setting it through the Dip-Switch block.

Some other items to note on this motherboard: It looks very familiar to the DFI P2XBL motherboard and because of the space given to the 3rd DIMM slot. Most likely they use 1 motherboard design for their other offerings, a good cost saving measure and it still maintains it's compactness. Instead of a line of medium to large capacitors, this board has few very tall capacitors placed in strategic places near the Slot-1 and the DIMM slots. This is the only board I've seen to date that has a slightly different colour for the AGP connector. Overall the board looks well done and the installation is a real breeze.

The given CD comes with the Hardware Doctor monitoring utility. Here are a few screen-shots:

The Manual has all the info on each jumper and connector assignment and it's purpose. So the installation part is of no problem. The section where it explains the Bios features are a bit lacking, in terms of completeness. Overall, the manual is Ok. The sticker of settings to be pasted in your casing is really helpful. No referring to the manual needed. Just open the PC-case cover and you'll find all settings information printed. Now that's something unique to DFI.

Test Configuration

Overall Rating (Out of a maximum of 5 Star)