Searching for the Memory Holy Grail: Part 1
by Wesley Fink on July 27, 2003 11:13 PM EST- Posted in
- Memory
Conclusion
If you plan to run DDR400 as your base memory speed with an 800FSB processor, your best memory performance will clearly be with four matched double-sided DIMMs. Our tests, confirmed by Intel White Papers, show these configurations ranked from fastest to slowest performance on an Intel 875 Canterwood or 865 Springledale chipset motherboard.| DDR400 (1:1) Performance | DIMM Configuration | Single-Channel or Dual-Channel |
| 1 | 4 DS | Dual Channel |
| 2 | 2 DS or 4 SS | Dual Channel |
| 3 | 2 SS | Dual Channel |
| 4 | 4 SS/DS Mixed Matched Pairs |
Dual Channel |
| 5 | Any DS | Single Channel |
| 6 | Any SS | Single Channel |
You can run mixed matched pairs of DIMMs. That is, two of one type and size and two of another type and size, but the performance can be significantly lowered. In our tests of mixed pairs, performance decreased 22% to 25% compared to four matched double-sided DIMMs.
If you do plan to use single-sided DIMMs, then make sure you run four matched DIMMs. A pair of single-sided DIMMs ranked third in our performance tests, and was almost as slow as mixed pairs.
The situation changes if you plan to run a 533FSB P4 Processor, or if you intend to run your memory at 333 or 266 Base (5:4 or 3:2 ratio). With a 533 CPU or asynchronous 5:4 or 3:2 memory ratio, the best performing memory configuration is two double-sided DIMMs. Based on Intel White Papers, memory performance with a 533CPU or 5:4/3:2 (333/266) is ranked from best to worst.
| DDR333/266 Performance | DIMM Configuration | Single-Channel or Dual-Channel |
| 1 | 2 DS or 4 SS | Dual Channel |
| 2 | 2 SS | Dual Channel |
| 3 | 4 DS | Dual Channel |
| 4 | 4 SS/DS Mixed Matched Pairs |
Dual Channel |
| 5 | Any 1 or 2 DS or SS (1 DIMM or 1 in each Channel) |
Single Channel |
| 6 | Any 1 SS | Single Channel |
While four DIMMs do not overclock quite as well as two DIMMs on an 875/865 board, we confirmed that the added memory bandwidth more than makes up for the slightly lower overclock with four double-sided DIMMs.
Now that we have determined the best Memory Configurations for 875/865 motherboards, we will look at the best performing high-speed memory in Part 2 of Searching for the Memory Holy Grail. Since we are still waiting for several new releases of DDR466 and DDR500 Memory, it will be several weeks until we can publish a reasonable comparison of the latest in high-speed memory. Stay tuned!
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Wesley Fink - Friday, August 1, 2003 - link
Thanks, Michael. Your comments are appreciated, since your memory reviews are always a "must read" for everyone in the industry.I got an idea for an article from your review of OCZ3700 GOLD at Lost Circuits. When it posts at AnandTech, I think you will find it interesting.
You may want to look at some of ThugsRook's game benches posted in the Forums here. As a skeptic he was trying to prove SS/DS made no difference in game benches. What he found, however, was that SS game benches were consisitently lower than DS benches. The differences were smaller than we see with SiSoft unbuffered, as expected, but they appear to be genuine.
MS - Friday, August 1, 2003 - link
Nice review, Wes.One single issue I have is that if you are running SiSoft unbuffered, you constantly hammer the memory, which means that the idle counter will not go in effect and you keep the maximum number of pages open at all times (I believe it is 32 combined to 16 wide pages in dual channel mode). This is really why you see the performance benefit with double-sided DIMMs.
However, in real life applications, this benefit is not present, at least as far as I can tell. No criticism intended, just a side-note.
Regards
Michael
p.s. and the guys who did some of the performance studies at Intel used to call me quite a few times .. :-)
Anonymous User - Friday, August 1, 2003 - link
This reads too much like an ad by OCZ - any non-OCZ users of the P4P800 Deluxe Asus board got a recommendation for best memory sticks to get stable, solid 1 gig of DDR333 (little, if any OC)? ThanksAnonymous User - Friday, August 1, 2003 - link
In fact OCZ announced PC-3700 Gold Quad pairs at 2003-07-03 for Intel 875 chipset.:SUNNYVALE, CALIFORNIA
OCZ Announces Dual Channel Gold Quad kits.
OCZ is pleased to announce the release of OCZ PC-3700 Dual Channel Gold EL DDR memory in 1GB kits featuring quad 256mb modules based on OCZ's recently developed Hyperspeed and Extended Voltage Protection (EVP) technologies.
OCZ HyperSpeed® technology denotes specific OCZ EL DDR ICs built and selected for their ability to run at the highest possible frequency. EVP protection allows the modules to tolerate higher voltage without compromising stability.
"OCZ PC3700 Gold has been a dominant product," said Steve Lee, Director of Strategic Business Development. "By offering hand-tested and matched quad 256mb modules, we have the best solution for dual channel configurations on the market."
OCZ Dual Channel Gold Quad memory will be shipping in 1GB PC-3700 Dual Channel optimized kits rated at CL 2-3-7-3 with an operating frequency of 2.75 volts. Each module is backed by OCZ's Lifetime Warranty and features a Gold layered copper heatspreader. The four matched 256MB modules are tested together on the Abit IC7-G to ensure maximum stability and performance.
OCZ Dual Channel Gold memory has been designed specifically for use with the Intel Canterwood and Springdale chipsets, and thus offers the best performance on these platforms
Wesley Fink - Wednesday, July 30, 2003 - link
512MB Dimms are usually DS, but that will be changing with higher-density chips coming out. @56MB Dimms are normally SS right now, but there are exceptions like OCZ 3700 GOLD which are 256MB and Double Bank. The last page of the article has charts which give recommendations from best to worst performance based on memory configuration. The data is from our own testing and the Intel White Papers.We will include some game benches in Part 2, but ThugsRook, who regularly posts in the Anand Forums, has posted some game benches at several sites showing the performance difference in SS and DS memory modules in gaming performance.
Anonymous User - Wednesday, July 30, 2003 - link
Thanks (#25) - I too have noticed that memory vendors claims and board manufacturer compatibility charts are often at odds - seems like it's left up to the builder to actually try it and see if it runs ... (ref post #19).Anonymous User - Wednesday, July 30, 2003 - link
I noticed that Asus in their P4C800 description (on their web page) says that some manufacturer's memory can only be used in certain configurations - some branda are limited to 2 sticks and some are limited in the total GB size.The reason they say is: "For optimum performance and overclocking stability". But if true it was rather surprising. For example, in the case of Kingston memory, Asus only two 512 sticks can be used.
I pointed this out to Kingston and they simply responded that four sticks can be used for a total of 2 GB. The tech ignored making any comment about the Asus statement.
So I suppose 4 sticks can be used as long as you run them at the stated settings. But I am not sure Asus means about "optimum performance".
Anonymous User - Tuesday, July 29, 2003 - link
Some real world benchmarks wure would have been nice, even if only 640x480 Quake3 numbers, just to get an idea if there really is a payoff to warrant the added cost that filling 4 banks vs 2 would entail.Anonymous User - Tuesday, July 29, 2003 - link
I'd also like to see what this means in the real world. I would be interested in some gaming benchmarks, particularly UT2003.Thanks for the excellent article!
Anonymous User - Tuesday, July 29, 2003 - link
Hey Prometheus, please check this asap:http://www.overclockers.com/tips00438/
great article btw ;)