Turbo Drive: Two Dual Boards with 2000 MHz
Редакция THG,  1 февраля 2001

A Rare Find: Dual CPU Boards


In the multitude of single processor motherboards, there is a small number of boards designed for dual CPU operation. These boards are particularly suitable for small graphics workstations or servers requiring high computing capacity and, at the same time, fast data transfers. However, in comparison with the boards for only one CPU, the dual boards are slightly more expensive: While a socket 370 board costs approx. $90 to $110 depending on its equipment configuration, a dual board will cost at least $140. To this you've got to add the cost for a second CPU.

Presently, there are two different chipsets on the market for the socket 370 platform supporting the operation of two processors: These include the Intel 815E and the VIA Apollo Pro 133A - also known as VIA 694XDP. In this context, we have thoroughly examined the Acorp 6A815D, the first dual board to be equipped with the Intel 815E, as well as the Asus CUV4X-D that works with VIA 694XDP. All the tests were conducted under Windows 2000 Pro, since Windows 98 SE and Windows ME do not offer multi-processor support. Let us state right now: This test brought not only exciting but also sobering results - but read for yourself!

VIA Northbridge

Only the special VIA northbridge variant offers dual processor support. While version VT82C694X is only suitable for single operation, version VT82C694XDP offers dual CPU support.

Intel 815E

Initially not intended for dual operation: Northbridge by Intel 815E.

Intel 815E or VIA 694XDP?

Chipset Intel 815E VIA Apollo Pro 133A Intel 820 Intel 840 Intel 440BX Intel 440GX
Release June 2000 November 1999 November 1999 October 1999 April 1998 June 1998
CPU platform Socket 370 Slot 1/Socket 370 Slot 1/Socket 370 Slot 1 Slot 1/Socket 370 Slot 1/Slot 2
Multiprocessor support yes yes yes yes yes yes
Northbridge Intel 82815 VIA VT82C694XDP Intel 82820 Intel 82840 Intel 82443 Intel 82446
Southbridge Intel 82801BA VIA VT82C686B Intel 82801AA Intel 82801AA Intel 82371EB Intel 82371EB
System bus clock (FSB) 66/100/133 MHz 66/100/133 MHz 66**/100/133 MHz 100/133 MHz 66/100/133* MHz 66/100 MHz
Memory clock 66/100/133 MHz 66/100/133 MHz 66**/100/133 MHz 100/133 MHz 66/100/133 MHz 66/100 MHz
Asynchronous memory clock yes yes no no no no
33 MHz PCI @ 133 MHz FSB yes yes yes yes no no
FSB Overclocking*** up to 166 MHz up to 160 MHz up to 155 MHz no up to 155 MHz no
max. number of DIMM or RIMM slots 3 4 2 4 4 4
max. Memory 512 MB 1536 MB 1024 MB 2048 MB 1024 MB 2048 MB
VC-SDRAM support no yes no no no no
DDR-SDRAM support no no no no no no
RIMM support (Rambus) no no yes yes no no
Dual Rambus support no no no yes no no
UltraATA/33/66/100 yes/yes/yes yes/yes/yes yes/yes/no yes/yes/no yes/no/no yes/no/no
Number of USB ports 4 4 2 2 2 2
Number of IRQs for PCI slots 6 5 6 6 4 4
Integrated graphics core yes no no no no no
AGP 1x / 2x / 4x yes / yes / yes yes / yes / yes yes / yes / yes yes / yes / yes yes / yes / no yes / yes / no
ACPI features yes yes yes yes yes yes

* overclocked
** not specified
*** depends on clock controller

This table shows a comparison of the most important dual CPU chipsets. Production of Intel 440BX and Intel 440GX has already been discontinued.

The table above lists the features of the most important chipsets offering multi-processor support. The latest candidate is the Intel 815E which, initially, was not designed for use as a dual platform. Rather, Intel was pinning its hopes on the Rambus-based chips i820/Camino and i840/Carmel which were, however, not accepted on the market because of their high price levels. What other options does a PC manufacturer have if he wishes to configure a powerful dual CPU system? At the moment, there are two low-cost solutions for equipping a board for dual operation with Pentium III. On the one hand, the VIA Apollo Pro 133A chipset can be installed in a special dual variant (Northbridge VT82C694XDP) or, alternatively, one reverts to the slightly more expensive Intel 815E which is, however, only capable of managing 512 MB of main memory.

Intel 815E or VIA 694XDP?, Continued

The direct comparison of both chipsets reveals many similarities. Both chips support variable clock speeds for the front side bus and memory speed. Overclocking proponents can (depending on the particular clock generator used) clock the memory up to 166 MHz, although in most cases system stability is not guaranteed. The score was level concerning functions such as AGP4x, UltraATA/100 and 4 USB ports, with both chipsets offering these features. Intel 815E's standard version is also offering onboard graphics, which is hardly worth mentioning because of its limited performance. The VIA Apollo Pro 133A also offers a unique selling point: It works with VC-SDRAM memory which you will hardly find on the market. This memory technology brought to life by NEC turns out to be rather unsuccessful. So much for theory - one glance at both test candidates reveals the details.

Acorp 6A815D

Acorp 6A815D is based on the Intel 815E chipset and also offers, in addition to AGP 4x and Ultra-DMA/100, variable clock speeds for the FSB and memory. Please note however that this board is a pre-production sample.

Asus CUV4X-D

The Asus CUV4X-D has similar attributes: AGP 4x, Ultra-DMA/100 and numerous clock speed settings.

Dual Twice: Acorp 6A815D and Asus CUV4X-D

The Acorp 6A815D is the first candidate equipped with two CPU sockets. It is based on the Intel 815E chipset. Not too much can be said about the final stage because this board is a very early beta sample. Because the board is equipped with an additional Promise controller chip, a total of four IDE interfaces with UltraATA/100 support are available. The placement of a total of five PCI slots seems sufficient, while the installation of the CNR slots appears more than questionable. Which customer or user who chooses a dual board as the basis for a powerful workstation will fall back on the low-cost CNR for which no corresponding cards are available yet either?

IDE Interface

Due to the additional Promise controller, the Acorp 6A815D is equipped with four IDE interfaces with UltraATA/100.

Promise Controller

View of the Promise controller connecting UltraATA/100 with Raid functionality.

The arrangement of both CPU sockets deserves slight criticism: They are both installed at an angle of 90° to each other, preventing optimum cooling air flow in the casing. However, the test did not reveal any thermal problems. In irregular intervals, the Acorp 6A815D refused to operate by just not booting again. Only pressing the power switch several times brought remedy. These deficiencies can be traced back to the early revision of this board, which was still fitted with numerous correcting wires on the underside.

Dual Twice: Acorp 6A815D and Asus CUV4X-D, Continued

Asus CUV4X-D Terminator

Asus CUV4X-D: A terminator has to be inserted into the second CPU socket for single CPU operation

Power Supply

The Asus CUV4X-D is equipped with an additional power supply slot which can be used for powerful OpenGL graphics cards.

AGP Pro Connector

The AGP Pro connector offers additional power supply for graphics cards. Aside from the 3.3 V standard, 1.5V are provided as well.

By contrast, the Asus CUV4X-D attracted much less attention by rendering its services reliably. A striking feature of this board is the AGP-Pro slot, which can also accept powerful OpenGL graphics cards because of its more stable and thus more powerful power supply. Since the CPU sockets are arranged at an angle of 90° to each other, just like the Acorp's sockets, basically the same applies: The flow of cooling air when installing in a PC casing is by no means optimum! Rather, additional fans should be installed to achieve optimum cooling. Compared to the Acorp 6A815E, the Asus CUV4X-D features four DIMM sockets, which allow maximum memory expansion of up to 1536 MB.

Overclocking Functions

Both boards offer the possibility to operate the front side bus beyond specifications. The BIOS offers extensive adjustment variations, while the Asus CUV4X-D seems to be user-friendlier. Since most Pentium III processors are equipped with a fixed multiplier, the processor can only be overclocked by an increase of the front side bus clock. For this purpose, both boards offer finely adjustable clocks for the FSB. Optimum cooling of the CPU allows overclocking the FSB to 150 MHz, which produces a processor clock of 1125 MHz (7.5 x 150 MHz = 1125 MHz) in case of the Pentium III/1000.

Test Configuration

Processors Two Intel Pentium III 1000 MHz
L2 cache clock 1000 MHz
Front Side Bus 133 MHz
Memory Clock 133 MHz
Memory Wichmann Workx PC133 SDRAM 256 MB CL2
(max. 1,1 GB/s transfer rate)
Motherboards ASUS CUV4X-D, VIA Apollo Pro 133A, Rev. 1.03
Bios 11/29/2000
ACORP 6A815D, Intel 815E, Rev. 0.2
Bios 12/21/2000
Graphics card NVIDIA Quadro 2 Pro
Treiber 6.5, DirectX 8.0
Sound Onboard sound disabled
NIC 3COM 3C905B-TX, 100 MBit
fHard disk IBM DTLA-307030, UltraATA/100, 30 GB
VIA 4 in 1 driversr 4.28 (Beta)
Software & Settings
OS version Windows 2000 Pro, Service Pack 1
Display resolution 1024 x 768 x 16 x 85
SYSmark 2000 Version 1.0, Patch 4
3D Studio Max R3 Rendering of ktx_race.max scene
Cinema 4D XL 5.3 Rendering/Animation of bottle.c4d scene
SUSE Linux 6.4 Linux Kernel Compilation

Benchmark Results and Discussion

Our test platforms are equipped with top-notch components promising high performance. Both candidates use two Pentium III/1000 which are supplemented by 256 MB of fast memory at 133 MHz (CL2) and a sinfully expensive Nvidia Quadro2 Pro graphics card (Elsa Gloria III, approx. $1100). However, this advantage in speed is only of great importance using selected applications such as 3D Studio Max or Cinema 4D. Otherwise, the deployment of a dual processor system is less noticeable than expected in daily usage. Although the results of Sysmark 2000 show slightly higher results during dual operation, the increase in speed remains under 10 percent.

Rendering Performance: 3D Studio Max R3

Rendering Performance: 3D Studio Max R3

While rendering under 3D Studio Max, the second CPU can use its full capacity on either board. The render time of the ktx_race.max scene is cut exactly in half due to the second CPU. Surprisingly, in comparing both chipsets, the VIA Apollo Pro133A comes in before the Intel 815E. This fact is most certainly due to the beta state of the Acorp board, meaning that this board is not yet performing to its full capacity.

Animation and Rendering: Cinema 4D XL 5.3

Animation and Rendering: Cinema 4D XL 5.3

Similar results are revealed using the Cinema 4D XL high-end program: The calculation of the test film sequence can be cut in half using a second CPU. Again, the Acorp using the Intel 815E chipset finishes after the Asus CUV4X-D using VIA Apollo Pro 133A. The reason for this result lies again in the Beta state of the Acorp board.

Office Performance: BAPCo Sysmark 2000

Office Performance: BAPCo Sysmark 2000

Applied standard for the office performance under Windows 2000 Pro is the BAPCo benchmark suite Sysmark 2000. However, this test does not execute multiple applications simultaneously. Consequently, the speed advantage of using two processors is minimal compared to single operation. Again, the board with the VIA 694XDP chipset finishes ahead of Intel 815E.

Linux Compilation

Linux Compilation

An interesting topic is the compilation of a special operating system kernel under Suse Linux 6.4, which is generally very processing-intensive and places high demands on the processor's integer unit. When using two processors, noticeable differences emerge compared to the single variant, with the speed being increased by over 60%! Just as with the other benchmarks, the board with the Intel chipset takes longer than the board with a VIA chipset.

Conclusion: Dual CPU boards Only For Special Applications

To keep it short: Dual CPU motherboards can only perform up to capacity in special applications. Included herein are rendering and animation programs that spread their processing load rather evenly on both CPUs. This fact is reflected impressively by our benchmark results from 3D Studio Max R3 and Cinema 4D XL 5.3. Otherwise, the utilization of a second CPU in daily operation falls short of the expectations. Even software for video editing - such as the popular Adobe Premiere - uses the capacity of two processors only minimally. An operating system supporting dual processor platforms is necessary in any case: Windows 2000 Pro and Windows NT 4.0 as well as Linux support this function. Nevertheless, the user profits from the application of a dual CPU system: A dual system shows significant advantages over the single system particularly when running several tasks simultaneously. The system load is much lower.

A direct comparison of the Intel and VIA chipsets reveals the following: In our test, the VIA Apollo Pro 133A dual version on the Asus CUV4X-D is slightly faster than the Intel 815E on the Acorp 6A815D. Since the Acorp board is an early Beta sample, no final conclusion can be drawn about its performance. That much is certain: A dual board is in any case more expensive than a model with just one CPU socket. The balance sheet comparing a dual CPU system to a single CPU system is shown in the table below.

Price comparison Single CPU platform Dual CPU platform
Processor, Intel Pentium III 1000MHz 290 580
Socket 370 motherboard 110 150
System memory, 256MB PC133 CL2 120 120
Graphics card, Nvidia GeForce Quadro2 Pro 1100 1100
Hard disk, IBM Deskstar DTLA 307030 140 140
Total USD 1760 2090

Example of a dual CPU system configuration compared to that of a single system. Especially the price for a second CPU makes a big difference and raises the cost of the dual system immensely.


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