RDram <-> DDRram   
 

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DDR SDRAM - fremtidens minne?

Vurdering Juli 2000

DDR vs Rambus

Intels forsøk på å dytte hele markedet over på Rambus-minne har ført til den største mediefokuseringen på en minnestandard noensinne. Rambus har blitt sterkt kritisert av media, og alle produsenter har vært motvillige til å begynne produksjon av denne dyre minnetypen, og å betale dyre lisensavgifter til Rambus Inc. Disse to faktorene har ført til at DDR har blitt stilt i et svært positivt lys. Men hvilken minnestandard vil være gjeldende om 2-3 år?

Med mindre Intel setter inn alle ressurser på å vri over markedet til Rambus, mener de fleste at DDR SDRAM har en lysere fremtid enn sin rival. For et år siden var de fleste usikre på om VIA og IBM ville greie å få etablert den nye minnetypen, men i løpet av det siste året har det skjedd mye interessant. AMD har lansert Athlon-prosessoren sin, og senere Duron og T-bird, og dermed har de kapret store deler av markedet. VIA har presset på for DDR SDRAM, og har også kapret store deler av chipsett-markedet. Dermed står de to firmaene i posisjon til å få presset gjennom DDR-minne.

En test utført av Inquest Market Research viser tydelig hvordan DDR-minne drar fra RDRAM i de fleste situasjoner. Applikasjonene som er testet er ikke så veldig avhengige av minnebussen, og dermed vil forskjellen ved vanlig bruk være mindre, men allikevel kan vi tydelig se at DDR drar fra RDRAM.

Foreløpige tester med Microns DDR-baserte Samurai-chipsett viser en ytelse rundt den til Intels i840, og noen ganger bedre. Når man da ser på prisforskjellen mellom et system basert på DDR-minne og et basert på Rambus-minne, ser man at man kan spare flere tusen kroner ved bruk av DDR SDRAM, som har en ytelse praktisk talt lik den til Rambus. Og enda mer interessant blir det når man skal sette sammen en server, som bruker enorme mengder med minne.

 
Rambus
PC133 SDRAM
Prisforskjell
64 MB
2465
822
299%
128 MB
3990
1650
241%
256 MB
10060
3320
303%

(priser per 23/7/00)

Ved å se på forskjellen i pris mellom Rambus-minne og dagens SDRAM-minne, kan vi få en pekepinn på den enorme forskjellen i pris på Rambus og DDR SDRAM. DDR-minne er ikke dyrere å produsere en SDRAM, og krever bare at minneprodusentene får seg bedre produksjonsutstyr. Derfor regner vi med at prisen på DDR-minne ikke kommer til å være stort dyrere enn det koster for SDRAM i dag.

Konklusjon

Minneprodusenter bør ikke gi opp DDR SDRAM, for markedet for akkurat denne minnetypen er enormt, og dessuten er overgangen fra SDRAM til DDR SDRAM adskillig enklere enn overgangen fra SDRAM til Rambus. Produksjonskostnaden er praktisk talt den samme som for vanlig SDRAM, mens RDRAM koster så mye at de fleste kunder ikke har råd til å kjøpe mer minne, selv om behovet er der.

Mot slutten av dette året ser det ut som om DDR-minne kan bli den etablerte standarden for PCer, men det gjenstår å se hvordan det går med blant annet VIAs og AMDs nye chipsett. Intel vil ihvertfall få store problemer med å snu trenden, og Rambus vil neppe noensinne oppnå full kontroll over markedet.

Billig ytelse på linje med RDRAM for prisen av SDRAM er en vinnende kombinasjon, så det ser ut som om ditt neste datakjøp vil involvere DDR-minne av en eller annen type.


Does it Really make a Difference?

Test October 2001

The Pentium 4 is known to crave memory bandwidth above and over everything else. The processor throws fits like a baby when there is not enough memory bandwidth, something which can often keep it from performing up to its potential. This was evident when Intel released their original i845 chipset which allowed a Pentium 4 to be run with conventional SDRAM (hint: avoid like the plague).

Often a P4 equipped with SDRAM, running at similar clock speeds could not beat a P3 at 1 GHz in terms of performance! DDR alleviated the memory bandwidth bottleneck somewhat with the i845D, delivering 2.1 GB/s worth of bandwidth as opposed to the 1.08 GB/s SDRAM offered. That is still a far cry from the 3.2 GB/s RDRAM can supply though, and today we're going to take a look at whether the i850 "RDRAM" chipset is that much faster then the i845D "DDR" chipset.
 

Many times readers have been writing in to ask; "Is RDRAM really necessary for a Pentium 4?" or maybe "I can't afford RDRAM, can I get by on DDR?" My personal favorite is; "I'm a speed freak on a budget, but can I get good performance with a P4/DDR combo? ".

Well today I hope we set these questions to rest and answer what has been on the minds of many; if Spiderman and Superman were in a battle who would win? We also plan on pitting RDRAM vs. DDR RAM and seeing which memory will be victorious - it is a battle royal that even the great Spidy can 'sense'.

There are a whole bunch of DDR chipsets now for the Pentium 4, but we're going to be focusing on Intel's own i845D. Why you ask? Intel has always produced fast and very stable chipsets (other then the i820) and the i845D is no exception. Based on the earlier i845 which was a very stable chipset in it's own, the i845D only brings DDR capability to the table and nothing else. Actually there are no real differences between the i845 or i845D. Sure there's an official revision difference, but basically the i845D is the i845 with DDR enabled.

The i850 board we are testing with is the nice red MSI 850 Pro5 which has official support for 400 MHz based Pentium 4's using the Socket 478 format. We had a few i845D based motherboards to choose from and eventually decided to keep it in the family and test on the MSI 845 Ultra. Our testing processor is a Pentium 4 2.0 GHz Williamette with 256KB L2 cache.

 

PCStats Test System Specs:
 

Computer Hardware:

 
Processor: Pentium 4 2.0 GHz
Clock Speed: 20 x 100 MHz = 2.0 GHz
Motherboards: MSI 850Pro5
MSI 845 Ultra
Chipset: Intel i850 (850Pro5)
Intel i845D (845 Ultra)
Videocard: MSI GeForce 4 Ti4600 (300/660)
Sound Card: N/A
Network Card:

N/A

Memory:

2x 128MB Samsung PC800 RDRAM
256MB Crucial PC2700 DDR RAM

Hard Drive: 40GB 7200RPM Maxtor D740X Ultra/133
CDROM: Panasonic 48x CD-ROM CR-594-B
Floppy:

Panasonic 1.44MB Floppy Drive

Heatsink: AVC Sunflower
PowerSupply: Antec 400W PSU
Software Setup: WindowsXP
VIA 4in1 4.38V
DetonatorXP 28.90
Benchmarks: SysMark 2002
Content Creation 2001
SiSoft Sandra 2002 Pro
PCMark 2002
3DMark2001SE
Quake III Arena

 

Please keep in mind when testing both systems, the memory options were set to the most aggressive settings allowed in the BIOS's.

 

Benchmarks: Sysmark 2002, Winstone 2001

 

BAPCO Sysmark 2002 Source:MadOnion / BAPco
 

 

SysMark2002 is more of an extension of SysMark2001 rather then a whole new benchmark. The applications used during testing have been updated and most importantly for AMD users, the new SysMark2002 uses the Windows Media Encoder 7.1 which supports the AthlonXP's SSE instructions.

 

 

BapCo SysMark 2002 Benchmark Results
  Internet Content Sysmarks Ranking
1. 850Pro5 (RDRAM) 245
2. 845 Ultra (DDR) 234
 

Office Productivity

   
1 850Pro5 (RDRAM) 151
4. 845 Ultra (DDR) 148

 

Here the differences between the RDRAM and DDR RAM is very little. So little that a user wouldn't notice the differences anyway.

 

Winstone 2001 Source: Zdnet
 

 

Content Creation Winstone 2001 keeps multiple applications open at once and switches among those applications. Content Creation Winstone 2001's activities focus on what we call "hot spots," periods of activity that make your PC really work--the times where you're likely to see an hourglass or a progress bar.

 

 

 

Winstone 2001 Benchmark Results
  Content Creation Scores Ranking
1. 850Pro5 (RDRAM) 72.6
2. 845 Ultra (DDR) 71.4

 

Since Content Creation 2001 is an office based benchmark, it acts a lot like SysMark2002 and can't really differentiate between the two systems.

 

Benchmarks: Sandra, PCMark 2002
Sisoft Sandra 2002 Source: Sandra
 

 

Sandra is designed to test the theoretical power of a complete system and individual components. The numbers taken though are again, purely theoretical and may not represent real world performance.

SiSoft Sandra 2001 Benchmark Results
 

Memory Benchmark

Score

5. Integer ALU - 850Pro5 (RDRAM) 2512 MB/s
5a. Integer ALU - 845 Ultra (DDR) 2045 MB/s
6. Float FPU - 850Pro5 (RDRAM) 2509 MB/s
6a. Float FPU - 845 Ultra (DDR) 2045 MB/s

 

Here Sandra reports that RDRAM has about 2.5 GB/s worth of bandwidth for both ALU and FPU while DDR only has about 2 GB/s of bandwidth. It's funny to see that DDR performing much closer to it's potential while RDRAM is still quite a bit off.

 

PCMark 2002 Source: MadOnion
 

 

PCMark is a new benchmark from our pals at MadOnion which a whole system benchmark. It can be used on desktop PC's, Laptops and even Workstations and tests everyday computing from home to office usage. PCMark specifically stresses the CPU, memory subsystem, graphics subsystem, hard drives, WindowsXP GUI (if WinXP is used), video performance and even laptop batteries. This benchmark was released March 12, 2002 and can be downloaded from Madonion if you would like to give it a test run on your computer for comparisons sake... don't cry to hard when you compare your numbers to the ones listed below!

 

PCMark2002 Benchmark Results
  Memory PCMarks Ranking
  850Pro5 (RDRAM) 4195
  845 Ultra (DDR) 3816

 

PCMark2002 prefers RDRAM over DDR RAM in its memory benchmark. It seems that RDRAM performs close to 10% better then DDR.

Benchmarks: 3DMark 2001 SE, QIII Arena

 

3DMark2001 SE Source: MadOnion
 

 

 

3DMark2001 SE is the latest installment in the 3DMark series by MadOnion. By combining DirectX8 support with completely new graphics, it continues to provide good overall system benchmarks. 3DMark2001 SE has been created in cooperation with the major 3D accelerator and processor manufacturers to provide a reliable set of diagnostic tools. The suite demonstrates 3D gaming performance by using real-world gaming technology to test a system's true performance abilities. Tests include: DirectX8 Vertex Shaders, Pixel Shaders and Point Sprites, DOT3 and Environment Mapped Bump Mapping, support for Full Scene Anti-aliasing and Texture Compression and two game tests using Ipion real-time physics. Higher 3DMark scores denote better performance.

 

3DMark2001 SE Benchmark Results
  Motherboard (FSB/Memory) 3DMarks Ranking
1. 850Pro5 (RDRAM) 10054
2. 845 Ultra (DDR) 9635

 

3DMark2001SE prefers RDRAM over DDR here but the performance differences are quite close still. In all honesty, we're a little disappointed that a P4 2 GHz with DDR and a Ti4600 couldn't break 10k.

 

Quake III Arena Source: ID Software
 

 

Quake III Arena is a First Person Shooter (FPS) that revolutionized gaming as we know it. Using multiple light sources and having graphics textures that can fill videocards, even after 3 years it's still able to bring a cutting edge system to its knees.

 

Quake III Arena Fastest demo001
  Video Card FPS Ranking
1. 850Pro5 (RDRAM) 271.6
2. 845 Ultra (DDR) 259.3

 

 

Quake III Arena Fastest nv15demo
  Video Card FPS Ranking
1. 850Pro5 (RDRAM) 74.1
2. 845 Ultra (DDR) 72.9

 

With the settings set to fastest the benchmark demo's become pure system testers. Here we can see from demo001 that there is quite a big performance difference between RDRAM and DDR. The nv15demo is more of a CPU tester, but still here we see that DDR is holding the processor back a little bit.

 

Quake III Arena MAX 1024x768 demo001
  Video Card FPS Ranking
1. 850Pro5 (RDRAM) 216.5
2. 845 Ultra (DDR) 209.7

 

 

Quake III Arena MAX 1024x768 nv15demo
  Video Card FPS Ranking
1. 850Pro5 (RDRAM) 51.1
2. 845 Ultra (DDR) 49.9

 

As the resolution is turned up the videocard starts to become the bottleneck (yes even a Ti4600!) and the differences are much closer.

The final conclusions; RDRAM vs. DDR RAM

So there we have it. RDRAM is faster then DDR RAM in all the benchmarks we performed, but the differences were quite small and would be unnoticeable to most people (except maybe gamers) unless of course they're benchmarking! Die hard gamers should be able to tell the differences between RDRAM and DDR RAM in some FPS games like QIII.

Since the performance of RDRAM and DDR are so close, it begs the question of which system is "best?" Memory prices can no longer be used as an excuse for not going with RDRAM since it's priced about the same as DDR, however RDRAM based motherboards are still somewhat more expensive and not as plentiful as their DDR counterparts, in numbers or in features (for the most part).

Of course for the extreme performance person (such as yours truly) where speed is number 1, RDRAM is the only way to go. It has the little extra "umph" and it's good for peace of mind!

One thing to keep in mind; we're using a 400 MHz based Pentium 4 Williamette which only requires 3.2 GB/s worth of memory bandwidth. The 533 MHz based Pentium 4's need 4.2 GB/s worth of bandwidth would make them even more bandwidth limited if teamed up with PC2100, or even PC2700 DDR RAM so the performance difference at 533 MHz when using RDRAM VS DDR RAM would be greater!

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Copyright © 2002 Øyvind Haugland
Sist endret:  13 januar 2019
 

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