» Computer memory types «

Intro

COMPUTER MEMORY
News & Views - Alternate & future memory - Links
This page will detail information about memory, in particular cutting edge and future memory types such as the cooler running 1.8v DDR-II's. As recently as September (2002) Intels own roadmap put DDR-II memory in circulation around Q2 2004, ramping up from there. Everything I have seen and read since then put this figure out of joint. I now estimate it rolling out around June 2004 onwards, in parity with SATA-II and PCI-Express, albeit in the form of: I can't get this f'love nor money… How much!? Grins nastily I bet it's still way cheaper than Rambus though! DDR-II is actually available now, commercially so from February 2003, albeit embedded in the GeForce FX's in the form of 500Mhz GDDR-II (Effectively 1Ghz!) I suspect the conservative dates for release dates from vendors has far more to do with avoiding class actions from share holders than actually getting the roadmaps wrong. Shrugs Update Aug 2003 I'll give this page another makeover soon, including adding picture of all the different memories for visual comparison.
Memory news and views
[Δ] May 2003 Hard facts about DDR-II The Inquirer had this interesting read on DDR-II. As much as anything it relates to the political bickering over standards but is does also go into detail about how it works. As shotgun answer, databases dislike it, games and graphics cards in particular can't get enough of it and it will start replacing all DDR memory Q2 next year so deal with it. Elpida gets Intel backing for DDR-2 According to the report Elpida will make 512Mbit DDR-2 chips with production starting in June this year, and aimed to work with its next generation microprocessor, codenamed Prescott. The time scales are bang and certainly Mike Magee knows his stuff, but "for Prescott", I dunno. Certainly the P5 due out in October (even September, I reckon) will want all mod cons to get the best out of it but that needs a whole new chipset and the Intel guys I've spoken with have been real coy. All things being equal, I can't see it, or I could but the feel I have is that the timeline is April 2004, maybe even May 2004, but absolutely no later. Despite what everyone else says (Intel included), I reckon the Grantsdale chipset will support second generation 300mb/s Serial ATA, DDR-2 memory AND PCI-Express and in the unlikely event this isn't so it's easy money that VIA and/or SiS will! Taken it as given that AMD will have complimentary chipsets for it's 64 bit technologies April 2003 Samsung memory is invariably at the cutting edge for research too. For example, in March of this year (2003) they announced mass production of DDR2 with the industry’s first 1 GigaByte DDR2 DIMM's
Memory news and views (2002)
[Δ] December 2002: DDR-II specific news Samsung has already made memory modules using 512 MB DDR-II SDRAM chips and expects to ship those modules in volume in late 2003. At present there are only really prototype chipsets or motherboards that support DDR-II, but I expect a number of announcements in March to change this. One of the main technical hurdles is that DDR-II signals are more susceptible to interference because line voltages in the 232-pin DDR-II systems are lower. Against this, it enables phenomenally fast data transmission speeds. Just to make things more awkward: [ http://www.ami2.com/shownews.asp?num=994" ] Officially there isn't going to be any DDR-II moniker. The industry has settled on labeling each successive new version of DDR by the higher frequency it represents: DDR-400, DDR-566, DDR-800 and on up the speed ladder. Within each speed grade, several feature options may exist - but essentially just as various features can be included or not on existing DDR devices. All down to deciding council snits, apparently. Shakes head sadly Children!!! Just so as we understand the above cough, The Samsung website lists DDR-II engineering samples on their November pricelists! XBitlabs says... (Read the full article from Dec 2002) K4T5104(08/16)3QM - 512Mb M-die DDR-II SDRAM General Description "The 512Mb Double-Data-Rate-II (DDR-II) SDRAMs are high-speed CMOS 512Mb Double Data Rate II Synchronous DRAM devices. The 512Mb chip is organized as either 32Mbit x 4 I/O x 4 banks or 16Mbit x 8 I/O x 4banks or 8Mbit x 16I/O x 4 banks device. This synchronous device achieve high speed double-data-rate transfer rates of up to 533Mb/sec/pin (DDR533) for general applications. The chip is designed to comply with the following key DDR-II DRAM features: (1) posted CAS with additive latency, (2) write latency = read latency -1, (3) Off-Chip Driver(OCD) impedance adjustment, (4) On Die Termination. All of the control and address inputs are synchronized with a pair of externally supplied differential clocks. Inputs are latched at the cross point of differential clocks (CK rising and /CK falling). All I/Os are synchronized with a pair of bidirectional strobes (DQS and /DQS) in a source synchronous fashion. A fourteen bit address bus is used to convey row, column, and bank address information in a /RAS//CAS multiplexing style. For example, 512Mb(x4) device receive 14/11/2 addressing. The 512Mb DDR-II devices operate with a single 1.8V ± 0.1V power supply and 1.8V ± 0.1V VDDQ. The 512Mb DDR-II devices are available in 60ball FBGAs(x4/8) and in 84ball FBGAs(x16). Auto Refresh (CBR) and Self Refresh operations of 8192 refresh cycles per 64ms are supported. (Refresh Period 7.8us)" From Samsung USA Related links: Samsung Semiconductor and Denali Software team up to accelerate Time-to-Market for DDRII-based memory systems. Search eMemory.com (Now Denali) (now gone!)for Samsung DDRII - several 512Mb chips (were) listed Getting late! I'll put in motherboard related information in the next day or so. Paul Dec 2002 SIS to introduce DDR II Pentium 4 chipset Micron demonstrate industry's first 0.11 Micron 1 Gigabit DDR SDRAMs [story link broken] Nov 2002: Here's me practically drooling at the thought of DDR-II next year when the cold water of realITy splashes in my face in the face or the upcoming ultra fast DDR-III's. OK, it's not until 2007 but hey, I never saw the past few decades go, three years is the blink of an eye for us wrinklies. The basics the JEDEC Solid State Technology Association are drafting include: 800Mbits/s and later increasing to 1.5Gbits/s. As little as 1.2 or 1.5V compared with 1.8V for DDR-II and 2.5V for current DDR. Feature short-loop through (SLT), a signaling technique to reduce noise at high frequencies. Density of the first DDR-III SDRAM chip is likely to be 4Gbits. Looking at 2005 to ratify the the standard for DDR-III, with sampling starting a year later and production in 2007. Check out the full article over at Silicon Strategies. Sept 2002 Here's an interesting article on DDR400 offerings from TwinMos and Crucial from The Inquirer Going back to April '99... Far Eastern DRAM makers ramped up production of 128Mb memory, following sharp falls in 64Mb prices. It only seems 10 minutes ago that the fire at the Kobe resin plant rocketed memory prices up to £70/Mb That's about £10,000 for the 128Mb wanted for Windows 2000, as opposed to the current (July '99) £70. Ah, the good old days!!! This month also saw Matsushita withdraw from the market. Due to poor yields at 800Mhz, Rambus added 700Mhz speed spec for Direct Rambus DRAM
Alternative & future memories
[Δ] Dec 2002: SIPP... SIMM... DRAM... SDRAM... ... and coming next MRAM Well, maybe. According to The Inquirer a number of memory companies including Japan's top two chipmakers, NEC and Toshiba are working next generation. One of the properties of MRAM (magnetic (or Magnetoresistive) random access memory), that makes it attractive to manufacturers is its ability to hold its contents after the power source is removed. The aim is to begin mass production of 256Mb chips within three years. Personally, I can't see it being fast enough myself and falling into niche markets. I'd put safe money on consoles for game saves mind. At best it's selling properties will shave a few seconds of a system restart, at worst if you have a bad crash and restart with the OS messed up in memory... Given that DDR's are already up to 1Gb and DDR-II will be available in up to 16Gb chips by the time MRAM is aimed at the market - - - in time for the DDR-III specs to be widely bandied. Well, you get the idea, hmmm! Nov 2002 Memory company Ramtron claims its ferroelectric random access memory (FRAM) is a new generation of nonvolatile memory that has the fast read/write speed and low power of battery-backed SRAM and eliminates the need for a battery. Apparently FRAM writes instantly, has virtually unlimited endurance, and requires very little write power. I vaguely reminder a similar - or related article saying the same thing. The only flaw was that the solution needed a unique crystal ore only know to found in some backwater county in Chekoslovakia! Anyway, read it in The Inquirer
Links
[Δ] My extensive list of memory vendors has been moved to the manufacturers section. [ http://www.ami2.com ] AMI2 - Advanced Memory International, Inc. An industry partnership enabling memory solutions for tomorrow's technology. EE ProductCenter The first stop for the latest IC's and Components (Formerly Chipcenter.com) CMTL - Computer Memory Test Labs OOhhh, he says, interested. They make a high end memory testing card now. If you have to ask the price... "MCFT is a self booting, operating system independent memory diagnostic card for exercising and testing RAM in AT 486 through the latest series of Intel Pentium, AMD Athlon, and Cyrix compatible processors. You can select from 4 levels different levels of testing which utilize 28 standard and proprietary memory test algorithms. Currently, MCFT supports all SIMMs, DIMMs, RIMMs, (SDRAM 66-150, DDR, DDR/2, RDRAM (RAMBus), SRAM, ECC, Parity and Non-Parity) and others. A major advantage of using MCFT, compared to stand alone testers, is the capability of testing RAM modules in a system. On many occasions, memory modules that pass stand alone testers will fail using the MCFT card. This is caused by the system chipset, noise, and several other factors. MCFT in this environment is the best, easiest, and fastest way to test system RAM. EE Times - Good news site (formerly EE Network) JEDEC - The guys that sort the standards Memtest86 - A Stand-alone Memory Diagnostic "Memtest86 is thorough, stand alone memory test for x86 architecture computers. BIOS based memory tests are only a quick check and often miss many of the failures that are detected by Memtest86." Ultra-X's Ramtest Pro This PCI card is one of the devices memory companies and repair shops etc use to test modules. R.S.T. Pro, is a Self-Booting, Operating System Independent diagnostic card for exercising and validating RAM of all types. Memory modules that pass standalone testers may still fail using R.S.T. Pro. This is caused by the system chipset, noise, and several other factors. R.S.T. Pro in this environment, is the best, easiest, and fastest way to validate, and test system RAM. Actually Ultra-X do a range of diagnostic tools, all of which I look every whenever I see them at events the CTO. Team DDR - Link now goes Micron The DDR Zone Samsungs DRAM division
Essential reading
[Δ] Here's a (dated) memory article I wrote on memory in 1999. Ace's Guide to Memory Technology (Thursday, July 13, 2000) : Part i Part ii: Latencies, latencies... Part iii: Asynchronous vs Synchronous Chipset Designs Ace's Guide to Memory Technology: Part 3 (Saturday, August 10, 2002) : Part i: DDR333, DDR400, DDR-II, and 32-bit PC1066 RDRAM Part ii: Architectural Details Part iii: DDR SDRAM and RDRAM Compared Part iv: Memory Comparison Continued Part v: DRAM Data Paths Part vi: RDRAM/DDR SDRAM Bank Comparison Part vii: Chipset Support Differences Part viii: Looking to the Future: DDR-II and Yellowstone: Part ix: Final Thoughts and Conclusion Ace's Hardware: IDF Fall 2002 (Saturday, September 14, 2002 ) : Part i: Dual Channel DDR, DDR-II, and RDRAM Part ii:Intel and DDR-II, Dual-Channel DDR, and More Part iii: RDRAM and Conclusion Granite Bay: Memory Technology Shootout (Several parts / pages)