Dual CPU systems are becoming more common these days and they are not limited to workstation or server applications anymore. One of the main reasons for that is the VIA chipset, which significantly lowers the cost of the dual socket motherboards. We looked briefly at the MSI 694D Pro as our first dual processor Apollo Pro 133A motherboard and found it to be a very impressive setup. We'll be doing a complete, in depth review of that board shortly, but in the meantime, we have proudly taken that as a reference point for other dual processor Apollo Pro133A boards.

Recently, however, we have received an even more interesting contender from Iwill, the DVD266-R. Although this motherboard looks more or less the same as the other dual Socket-370 boards we have in the lab, it caught our eyes because it uses the new VIA Apollo Pro266 chipset, which means that it supports DDR SDRAM.

Even though Iwill is one of the smaller motherboard manufacturers in Taiwan, they still provide strong competition for the big boys in terms of quality, features, and performance. A while back we reviewed the KV200-R (KT133) and the WO2-R (i815E), and both of them were rock solid during our tests. And their most recent board, the KT133A based KK266, is definitely an impressive one. Not only does the board live up to Iwill's reputation for quality and stability, but also offers outstanding performance to boot.

At about the same time, Iwill also became the first manufacturer to send us an engineering sample of the DVD266-R, a board that we first introduced in our Serverworks chipset review. In fact, up until this point, this board was still the only dual Socket-370 motherboard to find its way to the AnandTech Labs with the Apollo Pro266 chipset. Several manufacturers have informed us that more such boards are on the way soon, but none have arrived here so far. Before they do arrive, let's take a look at the preliminary version of the DVD266-R and see what Iwill has to offer this time.

Iwill DVD266-R
CPU Interface	Socket-370
Chipset	VIA Apollo Pro266 VT 8633 North Bridge VT 8233 South Bridge
Form Factor	ATX
Bus Speeds	66 - 200MHz (in 1MHz increments)
Core Voltages Supported	Auto Detect 1.60 - 2.05V (in 0.05V increments)
Memory Slots	4 184-pin DIMM Slots
Expansion Slots	1 AGP Slot 5 PCI Slots (2 full length) 1 ACR Slot
On-board Audio	C-Media CMI-8738
BIOS	Award Modular BIOS 6.00PG

The Need for Space

Click here to enlarge.

The MSI 694D Pro has a pretty large PCB, and the DVD266-R comes in even larger, slightly over 12 by 10 inches. However, Iwill did not waste any space on the PCB as you can notice tightly packed components.

Because of the size of the board, make sure your case is deep enough to hold the board and has enough clearance above the board for both CPU's. The four IDE connectors are located towards the front of the motherboard, so you must have enough space between them and the drive bays when the board is mounted, or the drive bays might block the cables.

Similar to the 694D Pro, one of the CPU sockets is placed to the right of the North Bridge while the other one behind the North Bridge. Unfortunately, some of the capacitors are located very close to the sockets, which could block the use of larger heatsink/fan units. Therefore, double check to make sure your HSF will fit on the motherboard beforehand.

Along the same lines, Iwill has picked probably the worst spot for the power supply connector - between the AGP slot and the CPU socket. When the CPU and video card are in place, it's extremely hard for you to plug or unplug the power supply connector, not to mention the fact that now the power cables will have to run over the memory and both CPUs, potentially affecting airflow over these critical components.

Notice how close the power supply connector is to the CPU socket and the AGP slot.

As mentioned earlier, the IDE connectors are at the front of the motherboard and do not block any expansion slots. Just be sure that the drive bays do not block them in your case since the board is fairly large. Unfortunately, the floppy connector is located on the left edge of the motherboard, a location that is far from ideal. With the current position, not only do you have to use a long floppy cable, the cable will now have to run under or over all the expansion cards.

Some of the connectors, including the front panel connectors, are placed horizontally in the front of the motherboard, which may block the use of longer PCI devices - something that is not uncommon in server applications. Ideally the connectors should be placed along the left edge of the board.

Last of all, the DDR DIMM slots are located quite close to the AGP slot, meaning that a longer video card will block the clip at the end of the DIMM slots. Unfortunately, that means that when if you ever want to upgrade your memory, you'll have to remove the video card first - a minor inconvenience, but one that could easily be avoided with a bit of planning on the motherboard designers part.

Two CPUs Need More Bandwidth

Compared to the Apollo Pro133A chipset, the Apollo Pro266 offers more memory bandwidth by utilizing DDR SDRAM. We saw in our review of the chipset review that Pentium III is not memory hungry, but two Pentium III chips together can potentially benefit from the increased memory bandwidth.

The VT8633 North Bridge is the heart of the Apollo Pro266 chipset with an integrated memory controller for DDR SDRAM and AGP 1X/2X/4X support. Similar to most current motherboards on the market, the AGP slot is not keyed specifically for 1.5V or 3.3V operation, so you should have no problem using almost any AGP video card in the market.

VT8633 North Bridge.

Iwill put in a total of four DDR DIMM slots on the DVD266-R, supporting up to 4GB of DDR SDRAM. In reality, however, that's not entirely possible because 1GB DDR SDRAM modules are not available just yet. But even with the 256MB modules that are available on the market today, you can still populate a maximum of 1GB DDR SDRAM, which should be enough for most users with today's applications. The fourth DDR DIMM slot did not work on our pre-production engineering sample, but that problem should be fixed by the time the board ships.

Similar to the Apollo Pro133A chipset, you do not need to use any kind of CPU terminator if you only want to use one CPU. All you need to do is make sure the CPU is in the socket labeled "CPU0". Also, like the Apollo Pro133A, the Pro266 allows you to run the FSB and memory bus asynchronously, meaning that you can still take advantage of PC2100 DDR SDRAM while only running a 100MHz FSB Pentium III.

Unlike the Apollo Pro133A, the PCI bus is no longer used to connect the North and South Bridges, but rather a dedicated "V-Link" bus connects them instead. The South Bridge is thus the VT 8233 and supports all the features of the 686B, including Ultra ATA 100, but also adds support for a total of six USB ports.

VT8233 South Bridge.

Iwill takes advantage of all those added features of the 8233 South Bridge on the DVD266-R. The two traditional USB ports are located at the back with the ATX I/O panel, while the other two USB connectors are found on the left edge of the motherboard. Since we received an engineering sample, we don't know whether Iwill will include the USB bracket that's required to take advantage of the additional USB ports.

The two traditional USB ports.

The second and thrid USB connectors.

As we're seeing more and more these days, Iwill has implemented an optional on-board IDE-RAID controller, the American Megatrends MG80649. The controller provides an additional two Ultra ATA 100 channels with support for RAID 0, 1, and 0+1 configurations.

American Megatrends MG80649 IDE RAID controller.

The 5/1/0/1 (PCI/AGP/ISA/ACR) expansion slots configuration is considered average, since we have seen boards with as many as six PCI slots. Instead of a sixth PCI slot, we see something very interesting here, an ACR slot.

The ACR slot is actually VIA's response to Intel's CNR slot, both of which are intended to provide cheaper communication devices. The advantage of ACR slot is that it is actually an inverted PCI slot, so manufacturers do not have to use a special connector, which would increase manufacturing costs. The ACR slot is still in the early stages of development, and we have yet to see how popular it will be, especially in light of the virtual failure of AMR and CNR card availability in the retail market. Of course, just like those other interfaces, it promises to allow OEM builders to produce cheaper systems.

Iwill always pays a lot of attention to on-board audio, and they continue to use the C-Media CMI8738 on the DVD266-R. It provides much better audio quality compared to host-based AC'97 audio. For the ultimate in sound functionality, we still recommend a dedicated hardware-based PCI sound card.

C-Media CMI8738 Hardware Sound.

Adding the Sweet

Iwill did a very good job in providing a wide range of FSB speeds, with settings between 66MHz and 200MHz in 1MHz increments, which is essential if you want to overclock your CPU(s) to the limit. To help with the overclocking, you can also adjust the CPU core voltage between 1.60V and 2.05V in 0.05V increments right in the BIOS. This voltage will be applied to both CPUs, unlike the MSI 694D Pro where you can choose different voltage for each CPU.

One thing we noticed about the DVD266-R is that no matter what voltage we set in the BIOS, it only seemed to affect CPU0. According the BIOS's report from the onboard hardware monitor, CPU1 always runs at around 1.5V. Since the CPUs are designed to run at 1.65V, this could be one reason for the instability that we experienced, but more on that later.

Notice Vcore B is only 1.52V while Vcore A is at default

Once again, keep in mind that too much voltage on a CPU can permanently damage it, and in general a 10-15% CPU increase in core voltage is considered acceptable. With most Pentium III's designed for 1.65V operation, that means that 1.8V or 1.85V is probably the highest voltage you want to use when overclocking. Unfortunately, the DVD266-R lacks I/O voltage settings, which sometimes comes in handy when trying to stabilize an overclocked system.

Our evaluation sample did not include a heatsink on the 8633 North Bridge, but mounting holes are present, so it's possible that this will change with production units. There are four fan headers on the board, two for the CPUs and two for chassis fans. Note that one of the chassis fan headers is located in the middle of the board, next to the DDR DIMM slots, which is not really an ideal place.

Iwill chose the popular Winbond W83627HF hardware monitor. Within the BIOS, you can monitor the speeds of up to three fans as well as three temperatures, including the two CPUs through the on-die thermal diode. It also shows the current battery voltage.

Winbond W83627HF

Just like the KK266, Iwill also included quite a few memory tweaking options in the BIOS, including 2-bank and 4-bank interleaving and CAS timing. If you have high quality PC2100 memory, you should be able to squeeze out another few percentage points of performance.

Memory tweaking options.

Possibly because this is an engineering sample, the stability of the board is far from ideal. The board features four 2200uF and ten 1500uF capacitors around the CPU sockets, but it crashed a total of six times in a 24-hour span under our stress tests, which is slightly below average. However, keep in mind that this is just an engineering sample, where we can still see some manual wiring on the board, so the final production version could be a totally different story.

There is still some manual wiring on the board.

Unfortunately, these stability issues also prevented us from performing in-depth overclocking tests. We were able to increase the FSB speed to around 136MHz, but the system lost stability quickly. At speeds higher than that, the system would simply refuse to boot.

The Test

In recent times, choosing a motherboard cannot be completely determined by a Winstone score. Now, many boards come within one Winstone point of each other and therefore the need to benchmark boards against each other falls. Therefore you should not base your decision entirely on the benchmarks you see here, but also on the technical features and advantages of this particular board, seeing as that will probably make the greatest difference in your overall experience.

Click Here to learn about AnandTech's Motherboard Testing Methodology.

With the help of some synthetic benchmarks, we notice some very interesting things. Remember that the first set of CliBench Mk III SMP 0.7.10 tests rely highly on CPU performance. With a dual CPU setup, this also relies on the quality of the SMP implementation, since we are running two threads at the same time.

These tests show the DVD266-R losing to the MSI 694D Pro in almost every category. This probably means that Iwill still has quite a bit of work to be done on the SMP implementation in order to really bring out the potential of the two CPUs.

Final Words

Only about a month after the release of the VIA Apollo Pro266 chipset, dual Socket-370 motherboards using the chipset have started to emerge. This is quite different from the release of the Apollo Pro133A, where such boards did not appear in the market for months after its release. This is likely because the Apollo Pro133A was VIA's first attempt at an SMP capable chipset, but now they've got all the kinks worked out. Therefore, don't be too surprised to see quite a few dual processor motherboards using the Apollo Pro266 chipset come out soon.

Iwill jumped out to be the first manufacturer to send us a dual Socket-370 motherboard using the Apollo Pro266 chipset, but we are not overly impressed. Although it brings us some decent performance numbers, there is still quite a bit of room for improvement, as we have seen in the synthetic benchmark tests.

Feature wise, the board integrates an on-board RAID controller and six USB ports, which is pretty impressive.

Stability is definitely the most important aspect to consider when dealing with server applications, and Iwill also needs to put in more effort with the DVD266-R before the final revision. They need a rock solid solution if they want to have any hopes of competing in this market. The layout of the DVD266-R could also be a concern for airflow and the use of longer PCI cards.

Last of all, price could also be a big factor with such a board and is another area Iwill will likely try to compete in. If dual processor motherboards using Apollo Pro266 are going to be significantly more expensive than those using the Apollo Pro133A, the performance gains of the Apollo Pro266 are probably not worth the extra cost in most cases.