Intel's new 845 chipsets

Intel has released three new variants of the SDRAM-supporting 845 chipset, aimed at different segments of the PC market. Here's a technical guide with all the details.
Written by Lori Grunin, Contributor
A PC's chipset may be low on your list of essential specifications when buying a computer, but Intel's latest 845 chipsets actually give you something to think about. The 845 has gone from the middle of the computing road to taking up every lane on the highway. You'd think that the consolidation would make PC buying decisions a little easier -- but, of course, it doesn't. One chipset, many flavours With flavours such as 845E, 845G, and 845GL, you'll now find some variant of the chipset in Intel-based systems for all market segments. The 845E chipset will populate the higher end of the Pentium 4 market in fast systems. The 845G will serve the mid-range segments of the market in consumer-orientated systems. Finally, the 845GL chipset will be used mainly in budget and corporate desktops where performance is a lower priority.
Intel's 845-series chipsets




Target market performance PC, mainstream PC performance PC, mainstream PC value PC
Processor Pentium 4 Pentium 4 Celeron
System bus (MHz) 533/400 533/400 400
Processor package mPGA478 mPGA478 mPGA478
Number of processors 1 1 1
Memory controller hub 82845E MCH 82845G MCH 82845GL MCH
Memory modules 2 double-sided DIMMs; DDR 2 double-sided DIMMs; DDR or SDR 2 double-sided DIMMs; DDR or SDR
Memory type DDR 200/266 DDR 200/266, PC 133 SDR DDR 200/266, PC 133 SDR
Max. memory (GB) 2 2 (DDR or SDR) 2 (DDR or SDR)
External graphics interface AGP (1.5V) AGP (1.5V) n/a
Integrated graphics type n/a Intel Extreme Graphics Intel Extreme Graphics
Dynamic video memory (MB) n/a 64 (if >= 256MB RAM), 32 (if <= 128MB="" RAM)<="" FONT=""/> 64 (if >= 256MB RAM), 32 (if <= 128MB="" RAM)<="" FONT=""/>
I/O controller hub type ICH4 ICH4 ICH4
PCI support PCI 2.2 PCI 2.2 PCI 2.2
USB ports/controllers 6 x USB 2.0 6 x USB 2.0 6 x USB 2.0

Choosing the right chip According to our performance testing, if we had to boil our recommendations down to bullet points, they'd go something like this: you'll get the best price/performance with 845E or 845G-based systems using one of the new Pentium 4 (at the high end) or Celeron (at the low end) processors. If you must get integrated graphics, make sure you choose an 845G-based system with an AGP slot (845GL systems really belong in a corporate 'never-to-be-upgraded' world), and always get at least 256MB of memory to compensate for what's stolen by the graphics subsystem. A closer look at the 845 chipset The new 845 chipset combines some forward-looking improvements with some frustrating limitations. All versions of the 845 come with the new ICH4 SouthBridge chip, which -- unlike the ICH2 in the 850E chipset -- provides support for up to six USB 2.0 ports. But like the 850E, the 845 still lags behind the times in its memory and disk I/O bandwidth: it can only use up to 266MHz DDR SDRAM rather than the latest 333MHz, and it incorporates an Ultra-ATA/100 drive interface rather than Ultra-ATA/133.

The 845G chipset, aimed chiefly at mid-range PCs, can support either integrated graphics or an external AGP card.
What's old, what's new Thanks to support for the top-speed 533MHz frontside bus (FSB) in addition to the existing 400MHz FSB, the 845E can run both the older Pentium 4 processors as well as the new 533MHz FSB-capable 2.26GHz, 2.4GHz and 2.53GHz chips that were announced with the RDRAM-based 850E chipset. The 845E officially supports only 200MHz and 266MHz DDR SDRAM, however -- a disappointment because 333MHz DDR is becoming widely available. The 845G chipset will serve the low to mid-range market segments. It supports the slower 266MHz DDR SDRAM and 133MHz SDRAM memory types, and it offers integrated graphics, dynamically allocating up to 48MB of system memory for use in the display subsystem (rising to 64MB with the new Extreme Graphics Driver 11.1, available in June). Motherboards using this chipset will also provide AGP slots for discrete graphics cards. What's borrowed: graphics memory Systems based on the 845GL are limited to a 400MHz FSB (and thus older Pentium 4 or the new 400MHz FSB Celeron CPUs) and the choice of using either 133MHz SDRAM or 200/266MHz DDR SDRAM. The 845GL's memory-dependent (up to 48MB) graphics will slow gaming/3D performance to a crawl, but that's typical for the low-end and corporate systems in which this chipset will reside. The 845GL will eventually replace the 810 and 815 chipsets currently common in this segment. What makes us blue Because the different 845 chipset flavours vary so widely in their capabilities, they're certain to confuse all but the most technically-knowledgeable users. All means that buyers are going to have to pay a little more attention to specifications. Furthermore, the jump to 1.7GHz and a 400MHz FSB for the Celeron means that its speed overlaps with that of low-end 1.6GHz Pentium 4 systems. At the high end, 845E-based systems with DDR SDRAM put pressure on 850E-based competitors with RDRAM because the latter are limited to PC800 (rather than PC1066) memory. We do see the expected 30 percent gap between RDRAM and DDR SDRAM in memory subsystem performance, but it doesn't (and probably won't) translate into significantly faster application performance -- even in CPU and memory-intensive MPEG-2-encoding tests, RDRAM-based systems are, at most, 10 percent faster than DDR SDRAM-based systems. What's slow: integrated graphics In addition to confusing buyers, the 845's contribution to integrated graphics is dubious. Application scores remain in the same ballpark as, say, systems using an nVidia TNT2 64 card. However, with the 845G/GL chip you lose up to 48MB of your system memory to graphics, rendering games unplayable. We couldn't run 3DMark2001 Pro (which tests DirectX 8 performance) on any integrated-graphics system, while Quake III performance leaped from around a useless 10fps for 810-based systems to a still-dismal 16fps with the 845G/GL. One thing at least is clear: never buy a system with integrated graphics if you want decent games performance.
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