Well, a new stream appeared in the mainboard society. This time the initiative belonged to AMD, which had announced its new Athlon processors on Thunderbird core and Duron designed for a new form-factor: 462-pin Socket A. Of course, the mainboard manufacturers couldn't remain aside and granted their immediate support to the newcomers, namely, started developing new products for this processor socket. Like in case of AMD Athlon launching, when ASUS, BIOSTAR, Gigabyte, MSI and FIC appeared the first to supply their solutions for this CPU, the same companies again ahead of all offered their products for Socket A. And a recommended mainboard list on AMD web-site mentions only BIOSTAR M7VKA, FIC AZ-11, Gigabyte GA-7ZM and Microstar MS-6340.

Today we managed to dig out one of the first mainboards for new AMD CPUs: Gigabyte GA-7ZM. Gigabyte company has already developed a couple of Slot A mainboards based on AMD 750 chipset as well as on VIA Apollo KX133. Now Gigabyte decided to support AMD another time and to introduce a mainboard for Socket A CPUs from AMD. So, Gigabyte once again expressed its vital intention to remain among the leading mainboard developers and manufacturers and proved that it held the position in the top three Taiwanese mainboard manufacturers not for nothing.

We are pretty interested in Gigabyte GA-7ZM, because it is the first mainboard on new VIA KT133 chipset supporting Socket A, we got for reviewing. So, first of all let's look at the specs.

Specification

• CPU
  • Supports Socket A AMD Athlon and AMD Duron CPUs with integrated on-die L2 cache, which work at 500-1000MHz and up
• Chipset
  • VIA Apollo KT133 (VT8363+VT82C686A)
• System memory
  • 3 168-pin DIMM slots of 3.3V supporting up to 1.5GB PC100/PC133 SDRAM and VC100/VC133 VCM
• AGP
  • AGP slot supporting 4x mode
• Slots
  • 1 AMR slot
  • 3 PCI slots corresponding to PCI 2.2 specification
• Integrated sound
  • Software AC'97 sound controller
• I/O ports
  • 1 FDD port, 2 serial and 1 parallel ports, ports for PS/2 mouse and keyboard
  • Joystick port, microphone line in and out
  • 2 built-in USB ports and two additional USB ports
  • IrDA TX/RX connector
• Integrated UltraDMA/66 IDE controller
  • 2 UltraDMA/66 Bus Master IDE channels (supporting up to 4 ATAPI devices)
• BIOS
  • 2Mbit Flash EEPROM
  • AMI BIOS supporting ACPI for Win98/Win2000, PnP, DMI and antivirus functions
• Other
  • Wake on modem, mouse, keyboard, LAN, USB-devices and timer
  • Hardware monitoring
  • 3 fan connectors
  • Suspend-to-RAM support
• Dimensions
  • MicroATX form-factor, 24.4x21.0cm

The mainboard is supplied in a standard blue-and-white box designed in Gigabyte's traditional way. The package includes UltraDMA/66 and FDD cables, illustrated user's manual and a CD-disk. The content of the CD is pretty poor: there is nothing besides the standard drivers and utilities. Unfortunately, Gigabyte hasn't yet followed the example of some other mainboard manufacturers who provide their products with some extra commercial software. However, it will hardly be necessary for MicroATX mainboard aimed primarily at OEMs.

Chipset

Since we haven't yet had a chance to speak about VIA Apollo KT133 chipset, let's devote a bit of our time to it now. Initially this chipset was known as KZ133, and in fact, it doesn't represent anything special. This is none other but VIA Apollo KX133 adapted for use in Socket A mainboards. That is why almost the only difference between KX133 and KT133 is the form-factor of the North Bridge microchip. The North Bridge of KX133 has 516 pins, which the North Bridge of KT133 has 552 pins. They probably had to increase the amount of pins of the main mainboard chip because with the old chipset with fewer pins it was extremely hard to arrange a planar four-layer connection of the 462-pin Socket A. Moreover, in its KT133 VIA changed some signal timings, which should supposedly make this chipset work better with Thunderbird based CPUs than its predecessor. As for the South Bridge, KT133 uses the same VT82C686A microchip.

However, KT133 still has a couple of problems. First, some mainboard manufacturers began complaining about instable operation of KT133 with 3 DIMM modules installed. The second problem noticed by the manufacturers was connected with overall instability of Socket A mainboards with CPUs working at the frequencies around 1GHz. Although these defects are most likely to result from some not very successful mainboard designs and not from the chipset errors, VIA will still have some difficulties with that.

By the way, strange as it might seem bearing in mind VIA's trouble, but the manufacturers can keep on using the old buddy AMD 750 in their Socket A products without any restriction.

As for the features of KT133 chipset, they don't differ from the features of KX133 (except the CPUs supported) that is why we will simply list them in brief:

• Supports AMD Athlon and AMD Duron CPUs
• 100MHz DDR EV6 system bus
• AGP 4x mode
• Up to 2.0GB 100/133MHz SDRAM and VCM
• PCI 2.2
• Integrated ATA 33/66 controller
• 4 USB ports
• Integrated AC-Link for AC-97 audio and HSP modem
• Integrated Super I/O controller and hardware monitoring
• Integrated keyboard controller and real-time clock
• ACPI and OnNow
• VT8363 North Bridge
• VT82C686A South Bridge

And in conclusion we would like to say a few words about VIA's plans concerning KT133 successors. First of all, the North Bridge of KT133 is pin compatible with KM133 due in the very near future, which is none other but the already familiar KT133 with the integrated S3 Savage4 graphics core like in the already announced VIA ProSavage PM133. Therefore mainboard manufacturers will be able to offer their new Socket A solutions with integrated graphics without redesigning their mainboards too much. Secondly, the South Bridge on the existing mainboards can be easily replaced with a new VT82C686B microchip, which unlike its predecessor will support UltraDMA/100.

Closer Look

But let's return to the mainboard, Gigabyte GA-7ZM. Although the chipset got renamed from KZ133 to KT133 for some political reasons, Gigabyte made up its mind to leave the name of its product as it was in order to avoid various confusions. So, please, meet GA-7ZM, one of the first mainboards with Socket A used for the new Low-End AMD Duron CPU and new AMD Athlon on Thunderbird core. Although in the very last minute AMD threw its Slot A Thunderbird processors into the mass market, Duron still needed a new mainboard. Gigabyte GA-7ZM, which supports not only the Duron but also socketed Athlon CPUs of up to 850MHz according to the list of recommendations on AMD web-site, has every chance to become this so badly needed product. Moreover, elder Thunderbird models should also work fine in this mainboard, because the information on AMD web-site refers to 2.2 revision while Gigabyte is already launching the third revision of GA-7ZM.

Actually, Socket A is practically of the same size as Socket7 or Socket370 and the only difference is the amount of pins. That is why you should be able to use old coolers with Socket A CPUs.

There are 3 DIMM slots on GA-7ZM, which support up to 1.5GB SDRAM. In fact, VIA Apollo KT133 supports 8 memory banks, which allows theoretically implementing 4 DIMM slots. However, Gigabyte preferred to avoid risks and to stick to PC133 specs advising the use of 3 DIMM modules. Frankly speaking, we checked the work of 3 DIMM modules in GA-7ZM and as we had expected the system didn't give us any cause for concern: it functioned perfectly.

Like in case of VIA Apollo Pro133A based mainboards, the BIOS of Gigabyte GA-7ZM allows setting the SDRAM working frequency equal either to 100 or to 133MHz upon the user's desire. Theoretically, VIA Apollo KT133 also allows clocking the memory for 66MHz, however, Gigabyte engineers considered this option unnecessary and didn't include it into BIOS Setup. Nevertheless, no matter what memory type you are using: PC100 SDRAM or PC133 SDRAM, you will have no problems with both. And of course, the higher is the memory working frequency, the higher will be the performance. Speaking about the memory, we should also mention that Gigabyte GA-7ZM also supports the exotic VCM SDRAM, which is a buffered multichannel PC133 SDRAM version currently manufactured only by NEC.

Since the clock multiplier of AMD Socket A CPUs is locked, the mainboard can boast very few means for the CPU configuring: a set of four dip-switches allows setting the FSB frequency. And that's it. Besides the base value equal to 100MHz and a couple of additional frequencies, you can also set it to 133MHz, which is very likely to be used in AMD processors.

Since Gigabyte GA-7ZM is made in MicroATX form-factor, it has not too many expansion slots. Besides the AGP 4x slot, there are only 3 PCI slots and 1 AMR slot. The mainboard doesn't have any ISA slots at all. The form-factor of this mainboard makes us believe that it should be aimed at OEM in the first place, that's why this amount of slots seems quite justified in this case. However, as for the ordinary users, they would be much happier with an ISA slot instead of the existing AMR, though it disagrees with PC99 specification. Two of the three available PCI slots allow installing full-size cards, and AGP slot has a typical for all Gigabyte mainboards retention mechanism holding graphics cards in proper position. Unfortunately, GA-7ZM isn't deprived of the traditional drawback characteristic of all KX133 based mainboards: with the graphics card installed into the AGP slot the DIMM clips appear blocked once and for all.

Gigabyte GA-7ZM has VIA 686A South Bridge. One of its functions deals with software AC97 soundcard realization. So, the mainboard is equipped with AD1881A codec from Analog Devices with a set of basic features. Although the software sound takes about 10% of the CPU resources, it makes the whole system much cheaper, because it allows abandoning an external sound card. If you belong to those users who don't want to sacrifice their CPU resources and are used to high quality sounding with a PCI sound card, then you can disable AC97 sound via BIOS Setup or with a special jumper.

As for the general mainboard design, it is pretty convenient to use and there are hardly any issues to mention (of course, if you have nothing against MicroATX form-factor). IDE, FDD and power supply connectors are located according to the ATX specification. The North Bridge of the chipset is equipped with a gold heatsink and here and there on the mainboard you can see a lot of capacitors improving the signal quality, which is very important because the system bus in Athlon systems transfers the data twice as fast as in Intel platforms. There is a yellow LED near the memory slots, which signals if the power in DIMM slots is on and warns the user against occasional manipulations with the equipment if the system isn't shut down. However, keeping in mind that PCI slots on GA-7ZM meet the PCI 2.2 specification and hence are powered even in standby mode, connecting this LED to the PCI power lines.

Gigabyte has recently started using AMI BIOS in its mainboards. This is one of the reasons why Gigabyte mainboards showed very high performance compared to their competitors. Gigabyte GA-7ZM is also not an exception and uses AMI BIOS version 1.22. The main peculiarity of this AMI BIOS version is the fact that it looks very much like a popular Award BIOS 4.51PG. However, unlike Award 4.51PG, which has always been known for a great lot of options for memory timings configuring, AMI BIOS has very few of them. Moreover, among other options available in GA-7ZM Setup, which are worth mentioning, we can point out just the possibility to disable AGP 4x. No AGP FastWrites enabling, no manual assigning of IRQs to PCI slots. Nevertheless, this makes the Setup page very easy to understand even for an unsophisticated user.

Hardware monitoring on GA-7ZM uses the features of the South Bridge, VT82C686A chipset. The system controls two temperatures, the rotations of two fans (there are three fan connectors on the mainboard, but one of them isn't monitored), and five voltages. The CPU temperature is taken by a special thermal sensor located in the middle of Socket A, because AMD doesn't provide its CPUs with an on-die thermal diode, as we can see by Intel.

Overclocking

EV6 bus used in systems built on AMD Athlon is not very overclocking friendly. The data is transferred along this bus at 200MHz and even the slightest frequency increase can result into system stability worsening. So, the best way to overclock AMD Athlon CPU is to change the CPU clock frequency multiplier. Theoretically, the clock multiplier of Socket A processors is locked in the core, however, it is possible to overcome this hardship. But it is not the easiest thing to do, because it deals with the mainboard BIOS programming. That is why far not all Socket A mainboards allow changing the CPU clock multiplier. To tell the truth, there are very few mainboards supporting this option. To our great discontent, Gigabyte GA-7ZM doesn't belong to these lucky boards. The only thing you can do with GA-7ZM is to slightly increase the FSB frequency.

Gigabyte has never developed any mainboards for overclockers. Especially since they would hardly be fond of MicroATX form-factor with very few expansion slots. All in all, it is not so bad that there is a block of dip-switches, which allows setting 8 values of the FSB: 95, 100, 105, 110, 113, 115, 117 and 133MHz.

GA-7ZM automatically detects CPU Vcore. That is why it is impossible to increase it in order to improve the overclockability, unfortunately. Moreover, the board doesn't allow operating the I/O circuits voltage.

In practice we managed to overclock AMD Duron 650 on our Gigabyte GA-7ZM up to 715MHz, by means of increasing the FSB frequency to 110MHz. Actually, this is all we achieved in terms of overclocking. The more we increased the frequency beyond this limit, the more unstable appeared the entire system. And then it simply refused to boot at all.

Performance

The results shown by the system built on Gigabyte GA-7ZM were posted in our AMD Duron 650 Review. Then we tested the CPU on this particular board.

As for the system stability, we don't have any complaints about it. At nominal frequencies Gigabyte GA-7ZM didn't face any hardships. Actually, we didn't expect any trouble to happen.

Conclusions

So, summing up our Gigabyte GA-7ZM review we have to stress that the major advantage of this mainboard is the fact that it appears the first Socket A mainboard for AMD CPUs. However, this board will hardly become a successful solution for progressive users because of its MicroATX form-factor and low CPU overclocking potential. But for OEMs it is a real treasure remarkable for its simple configuring options and high stability.

Highs:

• Supports new AMD Duron and AMD Athlon on Thunderbird core CPUs
• High stability and reliability

Lows:

• Very few expansion slots because of the MicroATX form-factor
• No additional means for CPU overclocking