It has been quite a while since we have seen a chipset from Intel that we’ve really liked.  After the release of the Pentium II back in 1997, every chipset after the original 440FX chipset seemed to improve on its predecessor and there was never a question of whether or not the latest chipset would be outperformed by its forerunner. 

Even at the peak of the BX chipset’s lifespan, there wasn’t much question about whether the forthcoming Camino chipset (now known as the 820) would outperform its predecessor.  Unfortunately, everything seemed to go downhill after the i820 chipset failed and the price of RDRAM was found to be between 3 and 5 times that of PC100 SDRAM, while offering virtually identical performance. 

Since then, Intel has introduced chipset after chipset that have failed to gain the recognition and support that we were used to seeing from motherboard manufacturers and the market alike. 

The i840 chipset, performance-wise, was a slight success, but there is a severe lack of support for the chipset among Taiwanese motherboard manufacturers.  Of the motherboard manufacturers that we visited at this year’s Computex in Taipei, only Iwill, quite possibly the smallest motherboard manufacturer in Taiwan, was shipping a measurable quantity of i840-based motherboards, and even then, they were only shipping around 500 of them a month.

The i810E was the only reasonably priced desktop chipset that Intel offered with 133MHz FSB support at the launch of Intel’s first 133MHz FSB Pentium IIIs.  The only real problem with the 810E was that it only featured the chipset’s integrated graphics solution whose performance was far below that of the mainstream graphics accelerators of the time.  This, combined with the fact that the chipset only supports a total of 4 rows of SDRAM (2 banks), shows that the 810E was obviously not targeted at the performance market that was begging for a decent 133MHz FSB chipset from Intel.

Attempts to bring SDRAM support to the i820/840 platforms failed miserably as the chip that made it all possible (MTH on the i820 and MRH-S on the i840) was causing quite a few compatibility problems, not to mention hindering performance incredibly. 

Because Intel was slipping in the chipset world, VIA managed to step forward with their Apollo Pro 133/133A chipsets and snatch a significant portion of the market.  VIA even went as far as to organize the memory industry in developing a PC133 SDRAM standard, something Intel didn’t even hold a part in. 

But if Intel was able to design a high performing SDRAM-based solution with the BX chipset, it didn’t make sense that they couldn’t bring a true successor to the BX with 133MHz FSB, PC133 SDRAM and Ultra ATA 66/100 support.  When we heard more about Intel’s “Solano” chipset earlier this year, we began to envision just that, a sort of ‘BX133’ chipset with Ultra ATA 66/100 support, killer performance and best of all, native PC133 SDRAM support. 

Now that the Intel 815 chipset is finally upon us, the real question is whether or not it is everything we imagined it would be.

Intel Hub Architecture

The i815 chipset is the fourth Intel chipset to make use of their Intel Hub Architecture (formerly known as Accelerated Hub Architecture - AHA).  The first chipset to use Intel’s Hub Architecture was the low-cost i810, followed by the i810E and then the 820/840 solutions as well as the recently released i820E.  For those of you unfamiliar with Intel’s Hub Architecture, here is an excerpt from our original i810 review: 

The key to the success of the Accelerated Hub Architecture is the substitution of individual hub interfaces for the PCI bus in connecting the various parts of your system to your memory/CPU on the motherboard end of things. Take a look at the acronym PCI, Peripheral Component Interconnect, it doesn't really scream "all-purpose-bus" now does it? Intel took what was once a two-chip solution (North/South Bridge) and converted it into a two chip, three-hub solution, the first implementation being the i810 chipset.

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The three individual hubs are the Graphics and Memory Controller Hub (GMCH), the I/O Controller Hub (ICH) and the Firmware Hub (FWH). The two main hubs, the GMCH and the ICH are connected via an internal bus that offers double the bandwidth of the PCI bus, 266MB/s. This is a definite improvement over the "old" way of doing things and will shortly become the new standard as far as chipsets go, don't expect Intel to return to the classical way of doing things on the motherboard level anytime soon.

That description of the AHA is pretty much universal and applies in almost every way to the i815.  The i815 differs from the i810’s Hub Architecture in that it uses a different Graphics & Memory Controller Hub (GMCH) (82815 vs. 82810), but it still supports the same ICH and FWH as the i810E and 820E. 

Graphics & Memory Controller Hub

The i815 features a unique Graphics & Memory Controller Hub that borrows from both the i810E and the i820E in terms of features.  From the i810E, the i815 takes its integrated graphics as well as its memory controller, which has been modified to support Intel’s PC133 SDRAM specification.  Keep in mind that there is a difference between VIA’s PC133 SDRAM specification and the one developed by Intel; however, the difference doesn’t seem to be significant.

The i815’s GMCH differs from its predecessors in that it supports an external AGP 4X slot like the i820/820E in addition to the integrated AGP graphics that separate the chipset’s GMCH from the i820’s regular MCH.  The presence of an external AGP 4X slot allows you to plug in a higher performance AGP graphics card, thus disabling the integrated video, and turns the i815 into a much more high performance desktop solution. 

You will also notice that unlike the i810/810E, the i815 does not feature an option for an on-board Display Cache.  The i810-DC100 and the i810E both featured a 4MB display cache running at either 100 or 133MHz depending on the chipset and was connected to the GMCH via a 32-bit dedicated bus.  The Display Cache could be used as the Z-buffer, thus freeing up system memory.  The i815 does not feature any such on-board display cache, but instead, the design calls for something known as a Graphics Performance Accelerator (GPA), which is essentially that 4MB display cache placed on a card that is inserted into your 815 motherboard’s AGP 4X slot (see below).

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However, most of you will not have to worry about the on-board Display Cache since you will probably opt for adding in your own external graphics accelerator instead of trying to take advantage of the integrated video of the i815.  The Intel 3D with Direct AGP graphics, as Intel likes to call it, has not really improved since the release of the i810/810E.  The only difference is that, now, it operates at a higher clock speed, provided that you are running at the 133MHz FSB.

Integrated Graphics Performance

So how fast is the i815's integrated video? There's only one way to find out:

As you can see, the 2D performance of the i815's integrated video is horrible, noticeably slower than even the old Riva TNT.

The integrated video is obviously not intended to be the fastest Quake III solution, but we will say that the i815's integrated video looked much better than what we noticed with the i810 under games like Quake III. But at 35 fps at 640 x 480 x 16, it's clear that you shouldn't be playing any games without an external graphics adapter on an i815 board.

The integrated video even makes the i815's SYSMark 2000 score take about a 6% drop in performance when compared to the same setup but with a GeForce 2. So you can see why we would use a GeForce 2 in our i815 benchmarks later on in the review.

The performance hit is much less noticeable under Content Creation Winstone 2000.

FSB & Memory Support

This brings us to the next feature of the 82815 GMCH, its Front Side Bus frequency support.  Unlike the i820/820E, the i815 chipset officially supports 66, 100 and 133MHz FSB frequency settings.  This makes the i815 Intel’s most flexible platform since it can run a 66MHz FSB Celeron, a 100MHz FSB Pentium III and even a 133MHz FSB Pentium III. 

Because the chipset officially supports the 133MHz FSB, it also features a 1/2 AGP to FSB ratio, which allows the AGP bus to continue to run within spec at 66MHz even while the FSB is running at 133MHz.  This is unfortunately one of the problems that keeps a decent number of BX motherboard owners away from the 133MHz FSB frequency.  Using the 2/3 AGP to FSB ratio (the lowest supported by the BX chipset), a 133MHz FSB keeps the AGP bus on a BX motherboard running at 89MHz, which can give some graphics cards a pretty hard time. 

Although the i815 chipset supports AGP 4X whereas the BX chipset only features AGP 2X support, as you can see by the below charts, the performance difference between AGP 2X and AGP 4X isn’t great enough to get too excited about.

The i815’s memory controller is a bit more interesting than the MCHs we’ve seen in the past.  The controller itself supports two memory frequencies, 100MHz or 133MHz.  So even if you are running a 66MHz FSB Celeron on an i815 motherboard, your memory bus will be running at 100MHz.  This gives the chipset a slight advantage over the BX chipset, which is incapable of running its memory clock at a separate speed from its FSB clock. 

Intel mentions that the 133MHz memory bus frequency can only be used alongside the 133MHz FSB, and while the motherboards we tested in lab only allowed us to use the 133MHz memory bus when the 133MHz FSB was selected, it is difficult to believe that a motherboard manufacturer wouldn’t be able to find a way around that limitation. 

Another interesting chipset limitation is that although the memory controller supports 6 rows of SDRAM (3 banks) that is only when PC100 SDRAM is used.  Intel only supports 4 rows of SDRAM (2 banks) when PC133 SDRAM is used.  What this means is that you are only supposed to be able to use two double-sided DIMMs when running at 133MHz, and if you insert three double sided DIMMs, the motherboard is supposed to default back down to the 100MHz memory bus setting.  None of the motherboards we’ve seen have done this with the exception of Intel’s 815 board, however we did notice a drop in stability when forcing the 133MHz memory bus with three double-sided DIMMs installed.  Our test system would experience random lockups and would fail to complete some tests.

I/O Controller Hub (ICH1)

The i815 uses the same i82801AA ICH that the i810 used.  The 801AA provides the functions normally reserved to the South Bridge of a chipset.  Here is an excerpt from our i810 review that explains the functions of the 801AA ICH:

The ICH is the connecting force between the PCI bus, the USB ports, as well as a newcomer to the motherboard, the AMR slot. The ICH provides a direct connection to the 2 IDE channels (4 devices), the 2 USB ports, the PCI bus, and the Super I/O which drives the keyboard, mouse, FDD, serial and parallel ports.

The ICH, supports Ultra ATA 66/33 and supports a maximum of 6 PCI slots with an optional ISA bridge. Although ISA bridges are supported by the chipset, it is highly unlikely that you'll see too many 820 boards outfitted with ISA slots.

Audio Modem Riser

It looks like 1/3 of an AGP slot, when in actuality it is the latest addition to the acronyms tech junkies will have to remember, AMR, or the Audio Modem Riser slot. The AMR slot allows users to take advantage of the chipset’s integrated Audio/Telephony codecs via a single card rather than wasting money on a software modem (à la Winmodem). 

The inclusion of the Audio/Telephony codecs allows motherboard manufacturers to produce Audio/Modem ready mainboards without having to actually test and certify the components on the Audio/Modem cards themselves. Then, after producing and releasing the board, an optional AMR card can be installed that will provide the output ports for the Audio/Telephony devices. The reason this is a more cost effective solution is because the Audio/Telephony devices are software devices that are essentially powered by your CPU. For some users, a soft modem or soft audio device makes sense, because how much of a Pentium III 600 will you be using while you're surfing the net? However, for others, it makes very little sense, such as having a soft audio/modem while playing some Quake 3 Arena on-line.

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Motherboard manufacturers will be offering hardware sound/modem devices as an option as well. Chances are that hardware sound will be a preferred option by gamers since you don't usually want to waste all too many clock cycles working on producing audio when they could be boosting your frame rate.

New I/O Controller Hub (ICH2)

Just like there were two versions of the i810 chipset, each with a different I/O Controller Hub, there are also two versions of the i815 chipset, again, each with a different I/O Controller Hub.  We have been talking about the i815 that uses the conventional ICH1 that we’re used to and that has been present on pretty much all i810E and 820 motherboards.  The i815E chipset, just like the i820, features the new 802BA ICH2 that adds Ultra ATA 100 support as well as an additional USB 1.1 controller (it does not support USB 2.0), which increases the total numbers of supported USB ports from 2 up to 4. 

A CNR Slot

One of the biggest features ICH2 supports is its integrated 82559 network core, which allows for 10/100 Ethernet or HomePNA ports to be placed on the motherboard at a relatively low cost since the core is integrated into the ICH2.  If a motherboard manufacturer doesn’t want to place the ports on the motherboard itself, they can take advantage of another supported feature of the ICH2, which is Intel’s Communication and Network Riser slot, otherwise known as CNR. 

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You can consider CNR to be the replacement for AMR as it can be used with modified AMR cards for the same purpose (CNR is not pin compatible with AMR), but at the same time it allows you to take advantage of the integrated 82559 network core without forcing the motherboard manufacturer to place an Ethernet/HomePNA connector on the motherboard itself. 

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Unlike AMR, CNR could end up becoming a very useful feature for AnandTech readers – if CNR cards become readily available online. 

Currently, most i815 motherboards will be using the ICH1 chip, but by sometime in the second half of this year, Intel expects the ICH2 to be in over half of all of the i815 motherboards that are shipping. 

The Firmware Hub (FWH)

The i815 also brings over the same i82802 Firmware Hub (FWH) as used on i810 boards, and, once again, the explanation is pulled from our original i810 review:

As you can tell by the name, the FWH is essentially the BIOS of the motherboard. The FWH is a 4Mbit EEPROM device with a bit of "intelligence" to it in that it does more than just store/retrieve predefined and modified settings, the FWH also contains Intel's own Random Number Generator (RNG). Programmers will be able to access the RNG in order to use it in developing encryption algorithms for encrypting credit card numbers for online shopping.  Intel's documentation claims that the RNG is used for "greater security," go figure, regardless, the RNG is there. 

There is a downside to the FWH, it happens to operate synchronously with the 33MHz PCI bus. This translates into another factor you must consider when you are overclocking the PCI bus to any degree. Although your PCI peripherals may work fine at a PCI bus frequency greater than 33%, if the FWH does not agree then you'll be in a bit of trouble. AnandTech's tests revealed that the FWH on most 815 boards is fairly reasonable when it comes to out-of-spec operation, however we issue no guarantees (it's overclocking, c'mon).

The Test

Note: The BX platform running at 133MHz FSB and the Celeron running at 100MHz FSB are both overclocked platforms and are not sold in that form on the retail market. Those performance numbers are only included for purposes of remaining thorough with our comparison.

As you can tell by the 1.9 point range of scores, your platform doesn't really matter when you're dealing with business applications and/or your basic set of content creation tools. If you find yourself in this position you'll want to go for the solution that will give you the least problems and be the most cost effective as well.

Under SYSMark 2000 the differences between the 100MHz FSB platforms and the 133MHz platforms start to become noticeable. Since the VIA 133A chipset is capable of running the memory bus at 133MHz while the FSB is running at 100MHz it comes in as the fastest 100MHz FSB solution in this comparison by a small amount.

In this case the BX chipset overclocked to 133MHz and the i815 running at its supported 133MHz FSB frequency come in tied for first place, both being faster than the cheaper VIA 133A solution as well as the much more expensive i820 setup.

Under Quake III Arena things get a little more interesting. Ideally the i815 running at 133MHz should be able to keep up with the overclocked BX chipset but as you can see by the 5.8 fps difference in scores, this isn't an ideal situation. Granted that a portion of that advantage is due to the fact that the BX chipset is running its AGP bus at 89MHz while the i815 is keeping it at the standard 66MHz, but the difference still shouldn't be that great.

The VIA 133A is also capable of edging out the i815 in performance as well, but once again it isn't able to compete with the two year old BX platform.

The more expensive i820 solution is still falling behind, it is clear that the i815 is a much cheaper and much better 133MHz FSB solution from Intel than the i820 + RDRAM platform.

As the GeForce 2's memory bandwidth limitation comes into play, the platform you're running on becomes less of a factor. In this case you're fine running an old 100MHz FSB CPU on a 100MHz FSB platform.

UnrealTournament is a very texture intensive benchmark, meaning it is also very dependent on a fast memory controller. Because of this the VIA 133A comes out just slightly behind the i815 at 133MHz FSB but does manage to pull ahead when the i815 is using PC100 SDRAM.

The good ol' BX platform when overclocked is still able to hold a small lead over the i815. If you're currently running a BX at 133MHz without any problems then there's no reason to even consider an upgrade to the i815.

The standings remain virtually identical at 1024 x 768 x 32.

Under Expendable we get another situation where the i815 pulls ahead of the 133A but still falls behind the overclocked BX133.

While we normally refrain from running synthetic benchmarks for our reviews we made an exception in order to provide some effective memory bandwidth numbers courtesy of SiSoft Sandra. The two benchmarks we used were the Integer and FPU memory bandwidth tests which both use the STREAM benchmarking core, a tried and true solution.

Here we get a repetition of what our real world benchmarks have been showing us all along. The overclocked BX chipset comes out on top, followed by the i815 and although most of our real world tests indicate that the VIA 133A can actually pull ahead of the i820 + RDRAM platform the Integer STREAM benchmark seems to indicate the exact opposite. This could very well be pointing out the weaknesses in VIA's memory controller which place the 133A below the i815 and BX chipsets in quite a few tests.

The standings change a bit in the FPU STREAM test as the i820 platform actually comes out on top. While we have yet to provide a real world benchmark that can support this data, the standings otherwise seem to be in agreement with what we've seen earlier.

Moving onto Windows 2000 and focusing on more high end applications we see that although there seems to be a decent sized range of scores, for the most part all 100MHz FSB platforms and all 133MHz platforms performed identically to one another.

Running Quake III under Windows 2000 doesn't change the standings much at all, although the i815 and 133A platforms do flip-flop their positions at the top of the chart.

Once again, with the GeForce 2's memory bandwidth being a bottleneck, the various platforms are performing within a couple of percent of one another.

As we get into the professional OpenGL tests you can see that there is a much larger range of scores that our 8 platforms are covering. At the top we still have the overclocked BX platform, closely followed by the i815 and then the i820 but this time around the 133A actually comes out as the slowest 133MHz (PC133/PC800) platform.

The overclocked BX setup regains the lead under the Design Review test and is followed by the i815 and i820 which are essentially tied in terms of performance. Once again the VIA 133A comes in last out of the top four.

The Data Explorer test has the overclocked BX platform at the head of the pack once again, this time followed by the i820 which actually holds a small advantage over the i815 setup. But in the case of a system that would be used for professional OpenGL graphics work, chances are that you don't want to rely on overclocking, in which case the i815 would make the most sense since it performs competitively with the top two solutions in the chart yet doesn't cost nearly as much as the second place i820.

The standings change slightly under the Lightscape test but basically there seems to be much more competition for that second place which is clearly behind the first place overclocked BX setup yet again.

The ProCDRS-02 viewset is the second SPECviewperf test in which the overclocked BX didn't come out on top as it was replaced ever so slightly by the i820 platform. The difference between the top three contenders, of which the i815 is included, is negligible though.

Conclusion

There is no question about it that motherboard manufacturers want the i815 chipset to succeed and they will do everything in their power to make sure that they have i815 and i815E based boards available for purchase provided that they can get enough chips to satisfy their orders.

As it stands now, if you were to go out and purchase a 133MHz FSB Pentium III CPU today your fastest overall platform would be the overclocked BX133. If you don't feel so comfortable running your AGP card so far out of spec or are afraid that your memory may not be able to handle it, then your next best choice would be the i815.

There is now no reason to even consider the i820 chipset. In the past there were some that could justify it by saying that they needed to have an Intel chipset and wanted 133MHz FSB support as well as the ability to use their own AGP cards, but now with the i815 chipset available there is no reason that the i820 should even garner any attention.

Looking towards the future, VIA does have a DDR SDRAM solution coming for the Pentium III/Celeron, the Apollo Pro 2000 and unless they really screw something up it should easily outperform the 8 platforms we compared here today. At the same time, if you're planning on buying an Apollo Pro 2000 based motherboard, plan on waiting a little longer than it would take for you to go out and pick up an i815 board.

Once again it comes down to whether you're willing to wait or you need to make the purchase soon. If the answer is soon then the i815 would probably be your best overall bet, if the answer is that you can wait then let's hope your current setup isn't too frustratingly slow.