Intel’s New CC820 Motherboard Review – THG.RU

Introduction

It’s only been a couple weeks since Intel finally launched their daunted i820 chipset. Just before the last attempt to launch this product Intel was plagued with a memory data integrity issue when more than two banks of RDRAM were installed. This problem being so close to the launch caused many headaches and a lot of money for all the motherboard manufacturers who had already designed and ramped up their products for Intel’s product announcement. Intel’s last minute decision to stop the i820 launch was e.g. too late for ASUS Germany to stop their i820 add-campaign, so that most of the adds still made it to print even though the product had to be redesigned! Since then motherboard manufacturers have been hectically scurrying about trying to revamp their motherboard designs and layouts to accommodate only two banks of Rambus (RDRAM) memory. The i820 chipset has been launched and the availability of motherboards should start hitting the store shelves within the next few weeks, but there is still one major dilemma for this product. This setback is the extremely high cost of the RDRAM memory required for the platform. I called around to some local vendors and here are the price ranges I received.

Given that the price for a 128MB of PC100 or PC133 SDRAM memory runs in the range of $150 – $250, RDRAM pricing looks quite scary. Especially since a person can go out and buy a descent, Athlon based, VIA based or Intel 440BX based, complete system for around $1000. Although the pricing of RDRAM should come down as time goes by, it sure has a long way to go.

i820 and the NEW! Memory Translator Hub (MTH)

Intel has obviously recognized that the price of RDRAM was going to be high, thus they designed and released an add-on chip, the 82805 Memory Translator Hub (MTH), which, when implemented on the motherboard, allows the use of PC100 SDRAM. No, that isn’t a typo! The i820 outfitted with the MTH will allow the use of PC100 SDRAM running the memory bus at 100MHz while the FSB runs at the higher 133MHz speed.

The MTH chip sits between the i820’s Memory Controller Hub (MCH) and the RDRAM memory slots. (Please refer to our i820 Chipset Review for a view of the i820’s chipset diagram.) The MTH is responsible for translating the data from the MCH to the SDRAM main memory. In order for the MTH outfitted i820 board to communicate with the SDRAM memory it has to go through the following scenario. The CPU has a 64bit wide parallel signal running at its FSB of 133 or at least 100 MHz. The information is then converted to the RDRAM’s 16bit wide serial signal in the i820’s MCH and then it gets passed through the MTH that changes the signal back to a 64bit wide parallel signal. Obviously this isn’t an actually sufficient way to communicate with the SDRAM. Getting data from the CPU to the SDRAM and back would be like you communicating with other people through a good old telegraph instead of using a telephone. Since the i820’s MCH was designed with just RDRAM in mind, this is the only way for i820 to communicate with SDRAM memory.

Because the MTH shares the same pathway as the RDRAM memory slots, it is possible for motherboard manufacturers to design i820 platforms that support both RDRAM and SDRAM. Supporting both memory types would require more real estate on the motherboard given the extra space required for the RDRAM RIMM slots, MTH chip and SDRAM DIMM slots. On motherboards that support both memory types the user will have to make a choice between RDRAM and SDRAM because mixing the memory types isn’t an option.

Intel’s CC820 Motherboard

The CC820 motherboard from Intel is their first platform equipped with the MTH. The MTH chip is located to the left of the IDE connectors and below the memory slots. By first glance this board can be easily mistaken for Intel’s VC820. Basically the only difference between the two boards is the memory support, SDRAM vs. RDRAM.

Intel CC820	Intel VC820

CC820 Feature Table

CC820 Performance Expectations

When I received the CC820 board I knew for sure that the memory translator hub would hinder the performance. The MTH acts just as a language translator would if you were giving a presentation to an audience that doesn’t speak your native language. I’ve had several experiences giving presentations to a non-English speaking audience through a translator. It takes some getting used to. First you rattle off a few sentences. Then you wait patiently while the translator communicates your words to the audience in their native language. Needless to say, it takes more time to pass on your information since your words have to be recompiled by the translator to another language. The same scenario is true for the 82805 MTH-chip. It has to take the data that was prepared for RDRAM and translate it for SDRAM memory. I figured that the performance of the CC820 platform would be a bit slower than an equivalently setup 440BX.

Comparing Intel’s CC820 platform performance

I thought it would be interesting to compare the performance of the CC820 to the RDRAM based VC820, a 440BX motherboard and a VIA Apollo Pro 133 Plus platform. Each of the boards was run with a Pentium III 600MHz processor, 128MB of main memory, Western Digital AC418000 UDMA Hard disk, and an NVIDIA GeForce 256 DDR reference board. The test suite included, SYSmark98 under Window98 and NT, and Quake III Arena Test (DEMO1 & DEMO2) along with Descent III. This suite of tests should give us a great idea of the overall real world performance each of the platforms has to offer. Each of the 3D gaming applications was run at 640x480x16 resolution. The reason we only run this lower resolution is to eliminate the graphics board as the bottleneck, since our goal is to show the performance differences in the platforms. If higher resolutions were run on each of the platforms then all of the scores would end up being the same due to the limitation of the graphics adaptor.

Test Setup

Business Application Performance – Window 98SE

Under Windows 98 the i820 SDRAM based platform (CC820) performs about 5% slower than Intel’s older 440BX chipset.

Business Application Performance – Window NT SP5

The NT results look much like the 98 results. The i820 SDRAM platform still scores the lowest, 5% slower the 440BX.

3D Gaming Performance – Windows 98SE – Quake 3

WOW! The i820 SDRAM board scores over 13% slower than all the other platforms. Looks like the MTH is putting a strangle hold on the memory throughput.

3D Gaming Performance – Windows 98SE – Quake 3, Continued

For fun I ran the DEMO2 script as well. The outcome is identical to DEMO1. The CC820 platform (SDRAM) scores over 13% behind the competition including the older 440BX.

3D Gaming Performance – Windows 98SE – Descent 3

Every 3D title in our suite of tests, including Descent 3, shows that the new CC820 platform performs well below the others.

Conclusion

The Intel CC820 based board provides a fairly decent set of features: AGP 4X, lower cost SDRAM memory and UDMA66. However, the performance is absolutely horrible, especially in 3D intensive applications (over 13% slower than 440BX). The poor CPU and AGP buses (>1GB/s) are starved for data from the slowed down main memory.

What good does a 133MHz FSB and 4X AGP give you when the main memory can’t keep up? It’s obvious that the 82805 (MTH) was an afterthought from Intel. Just a patch to allow the system integrators a vehicle to push i820 based platforms combined with the Coppermine processors at a reasonable price.

The best bang for the buck, as far as Intel platforms go, is with a VIA Apollo Pro 133 or Intel 440BX platform. Both of these clearly outperform the CC820 (SDRAM) and keep pace with the VC820 (RDRAM). The price of RDRAM will have to come way down before i820-based platforms become a competitor with VIA, 440BX or Athlon based platforms.

I certainly wouldn’t purchase an i820-based motherboard just yet. Not until RDRAM pricing comes WAY down and/or there is proof of its superior performance. I just can’t see spending $900 + bucks for 128MB of RDRAM memory. Especially since the performance advantage is minimal if any…